Dipolar cycloaddition reactions of diazoindene and

Dipolar cycloaddition reactions of diazoindene and the thermal behavior of the cycloadducts ALBERTPADWA'AND STEVENI. GOLDSTEIN Department of Chemistry, Emory University, Atlanta, GA 30322, U.S.A Received February 7 , 1984

Can. J. Chem. Downloaded from www.nrcresearchpress.com by 91.75.84.192 on 06/03/13 For personal use only.

This paper is dedicated to Professor Peter Yates on the occasiorz of his 60th birthday

ALBERT PADWA and STEVEN 1. GOLDSTEIN. Can. J. Chem. 62, 2506 (1984). A study of the dipolar cycloaddition behavior of diazoindene toward electron-deficient acetylenic and olefinic dipolarophiles has been carried out. Reactions with alkynes afford transient 1,3-dipolar cycloadducts. Product formation can be attributed to a substituent-dependent partitioning between spiro 3H-pyrazole adducts and ring opened diazoalkenes. The initially formed cycloadducts lose nitrogen to give a spirocyclopropene derivative or undergo the van Alphen - Huttel rearrangement. When olefinic dipolarophiles are used, nitrogen deficient 1 : 1 adducts are isolated. The formation of the product involves the further loss of nitrogen from the initially formed spiropyrazoline adduct. ALBERT PADWA and STEVEN I. GOLDSTEIN. Can. J. Chem. 62, 2506 (1984). On a rialis6 une Ctude du comportement, lors de reactions de cycloadditions dipolaires, du diazoindkne vis-a-vis de dipolarophiles olifiniques et acCtylCniques deficients en Clectrons. Les reactions avec les alcynes fournissent des cycloadduits 1,3-dipolaires intermediaires. On peut attribuer la formation de ces produits ?I une partition, qui depend des substituants, entre les adduits spiro 3H-pyrazoles et les diazoalcknes cycle ouvert. Les cycloadduits qui se foment initialement peuvent soit perdre de I'azote pour conduire a un derive spirocycloprop&neou subir une transposition de van Alphen - Huttel. Lorsqu'on utilise des dipolarophiles olkfiniques, on isole des adduits 1 : I deficients en azote. La formation du produit implique une perte subsequente d'azote par I'adduit spiropyrazoline qui se forme initialement. [Traduit par le journal] Higher order dipolar cycloadditions of diazo compounds can occur when the diazo system contains more than four 7 ~ electrons ( 1 - 12). The use of extended diazoalkanes with six or more electrons has received little attention despite the obvious synthetic and theoretical interest in such processes. Selection rules for higher order dipolar cycloadditions are similar to those of the corresponding isoelectronic polyenes and are allowed in the suprafacial-suprafacial mode when the total number of participating electrons is 4 n + 2 (13, 14). Derivatives of the diazocyclopentadiene and certain diazoazole ring systems are ideally suited to a study of the various possible modes of extended dipolar cycloaddition. As part of a general program to study profiles of reactivity of diazoalkanes (15-17), we became interested in determining whether diazoindene (1)could undergo a higher order dipolar cycloaddition reaction. This paper summarizes our observations in this area.

-

Results and discussion Diazoindene 1 could in principle react with acetylenic dipolarophiles via several plausible pathways: by either or both of two competing modes (1,3 or 1,7) of cycloaddition giving respectively 2 or 3, or via loss of nitrogen to give the carbene derived product 4. Previous work in this area has shown that while the analogous diazacyclopentadiene system reacts almost exclusively by 1,3-addition to acetylenes (7- lo), the azaheterocyclic analogues give products resulting from 1,7-cycloaddition (1, 2). In an effort to establish the preferred mode of cycloaddition, we allowed diazoindene 1to react with dimethyl acetylenedicarboxylate. The cycloaddition was carried out in benzene solution and the reaction was monitored qualitatively by the disappearance of the diazo compound according to both infrared and tlc analyses. The reaction of 1 with dimethyl acetylenedicarboxylate furnished (94%) dimethyl Z-diazo- 1H-

4

'Alexander von Humboldt Senior Visiting Scientist, University of Wurzburg, 1983- 1984.


PADWA AND GOLDSTEIN

inden-1-ylidenebutanedioate(6). The formation of 6 can be regarded as proceeding by an initial 1,3-dipolar cycloaddition followed by a thermally allowed (3+2)-cycloreversion (for a review of 1,3-dipolar cycloreversions, see ref. 18). The conversion of 1 to 6 represents an interesting example of a 1,3-dipole metathesis process since the diazoalkane obtained is different from the one used initially (19).' Structure 6 liberated nitrogen on heating in benzene to give spirocyclopropene 8. This reaction undoubtedly involves cyclization of the initially formed vinylcarbene intermediate 7. The thermolysis of vinyldiazomethanes is well known to give cyclopropenes as products, thereby providing a good analogy for this process (20). Heating a sample of diazoindene 1 and dimethyl acetylenedicarboxylate at 80°C for longer periods of time produced a 2: 1 adduct (i.e. 9, 92%) in addition to spiroindene 8. The formation of 9 is believed to proceed by cycloaddition of 1 onto spirocyclopropene 8. This could be confirmed by allowing 1 to react with a sample of 8 at 25°C. When diazabicyclohexene 9 was heated at 160"C, nitrogen was lost and the major product obtained corresponded to diene 11. The formation of 11 can be viewed in terms of a process involving initial carbon-nitrogen bond cleavage to yield zwitterion 10 followed by loss of nitrogen to give diene 11. This reaction is similar to that encountered on thermal or photochemical decomposition of related derivatives of 2,3-diazabicyclo[3.l .O]hex-2-enes (2 1, 22). 'NO signs of the initially formed cycloadduct 5 could be detected in the crude reaction mixture.

There are a number of reports in the literature which describe 1,3-dipolar cycloadditions to cyclopropene derivatives (21 43). The rates of these 1,3-dipolar cycloadditions are quite high, indicating that considerable strain in the olefin is relieved in the transition state for addition (43). The initial cycloadducts often rearrange by valence bond tautomerization, and secondary products are frequently isolated. In view of our interest in the cycloaddition behavior of cyclopropene derivatives (44), we initiated a study dealing with the reaction of 8 with several dipoles. When spirocyclopropene 8 was treated with diazomethane in ether solution at 25"C, a clean cycloaddition reaction occurred to give diazabicyclohexene 12. Thermolysis of a sample of 12 at 110°C in benzene or photolysis in benzene resulted in the formation of the isomeric diazabicyclohexene 13. Interestingly, structure 13 could not be isomerized back to 12 on heating or on irradiation. The stereochemistry of the individual isomers could be readily discerned by examination of their nmr spectra. The appearance of the 6-endo proton in 12 (6 3.98) at high field relative to proton H6 in 13 (6 5.13) is compatible with the anisotropic shielding of this proton by the adjacent aromatic ring. As is the case with most 1,3-dipolar cycloadditions ( 4 3 , the 1,3-dipole added from the least hin&red side of the =-bond to give structure 12. An attractive rationale for the interconversion of 12 to 13 (Path A) involves an initial cycloreversion to give 14 followed by a subsequent intramolecular cycloaddition. An alternate mechanism (Path B) consists of cleavage of the cyclopropane ring to give diradical 15, which undergoes ring flipping followed by ring closure. This path seems less likely since diazabicyclohexenes are

CAN. J. CHEM. VOL. 62. 1984


2508

known to produce P,y-unsaturated diazoalkenes on heating (21, 22). In fact, the thermolysis of a sample of 12 at 145°C produced diazoalkene 14. The nmr absorptions due to 14 disappeared on standing at room temperature, cleanly reproducing the spectrum of 13. These results clearly indicate that the intramolecular dipolar cycloaddition reaction of 14 is highly stereoselective and produces the thermodynamically more stable diazabicyclohexene isomer. A related set of results was encountered when spirocyclopropene 8 was allowed to react with 2-diazopropane. We also

found that 8 gave the dipolar cycloadduct 17 when treated with . a-chloroacetaldoxi~nein the presence of triethylamine. Silica gel chromatography of 17 produced the isomeric oxadiazabicyclohexene 18. A similar rearrangement occurred when 17 was stirred in benzene with a trace of p-toluene sulfonic acid. 'The stereochemistry of cycloadduct 17 was easily assigned on the basis of its nmr spectrum. The appearance of the indenyl proton in 17 at a higher field (6 5.80) than the corresponding proton in 18 (6 6.57) is consistent with the expected shielding effect of the C=N double bond. Thermolysis of 17 (or 18)


PADWA AND GOLDSTEIN

I

A benzene

results in the loss of acetonitrile and formation of enone 20. The isomerization of 17 to 18 is an interesting transformation and merits some discussion. The reaction most likely involves cleavage of the central bond of the cyclopropane ring to give 19, which undergoes ring flipping followed by a subsequent ring closure. In an effort to establish the regiochemical cycloaddition behavior of diazoindene, the reaction of 1 with methyl propiolate was investigated. In this case the cycloaddition produced a complex mixture of products which could be separated by silica gel chromatography. The products were assigned as indazole 21, pyrazoloquinoline 22, and diazoalkenes 23 and 24 (E,Zmixture). The structures of 21-24 were in accord with the nrnr, uv, ir, and mass spectral data (see experimental section). Heating diazoalkenes 23 and 24 in a sealed tube in benzene at 160°C produced pyrazole 22, benzylidene indene 25, and spiroindene 26, respectively (see Scheme 2). The mechanism by which these reactions proceed is worthy of comment in view of the diversity of structures obtained. We believe that the initial reaction involves a 1,3-dipolar cycloaddition of 1 with methyl propiolate to give a mixture of regio-

I

A benzene

isomeric cycloadducts (i.e. 27 and 28). The reactions of simple diazoalkanes are generally HO (1,3-dipole) - LU (dipolarophile) controlled (46) (Type I process (47)). 3-Substituted pyrazolines are the major products produced, a result of union of the larger diazoalkane HO coefficient on carbon with that of the larger dipolarophile LU coefficient on the unsubstituted carbon (46). We suspect that the formation of a mixture of regioisomers (vide infra) is a result of the Type I1 dipolar cycloaddition behavior of diazoindene 1 (Sustmann's classification (47)). Introduction of an aryl group onto diazomethane is known to result in a mixture of regioisomeric cycloadducts (45). The initially formed cycloadduct 27 aromatizes under the reaction conditions via a thermally allowed 1,5-sigmatropic shift of the phenyl group to give compound 21. Interestingly, this type of isomerization (van Alphen - Huttel rearrangement), for which ample precedence exists (48,49), proceeds by exclusive migration of the phenyl bond to the carbon atom. The major path followed by 27 involves a 3+2-cycloreversion to give diazoalkene 24. Further heating of this material in benzene results in the formation of spiroindene 26. The formation of 26 involves loss of nitrogen followed by carbene addition across

CAN. 1. CHEM. VOL. 62, 1984

2510


the T-bond of benzene to give a transient norcaradiene intermediate (i.e. 29) which rearranges to 26 via a vinylcyclopropane-cyclopentene rearrangement. The isomeric cycloadduct (i.e. 28) obtained from the initial 1,3-dipolar cycloaddition could not be isolated. It is assumed that this species is converted into diazoalkene 23 by means of a 3+2-cycloreversion. A control experiment showed that 23 is

1

-N2, benzene

As an extension of our studies with diazoindene 1, we also investigated its cycloaddition behavior with electron deficient alkenes. In each case, nitrogen deficient 1 : 1 adducts, the structures of which have been assigned as the spiro-cyclopropylindenes 32-36, were isolated in yields of 80-95%. Whereas the reaction of 1 with methyl acrylate (or nitroethylene) afforded a mixture of stereoisomers, diazoindene gave rise to a single product when diethyl fumarate was used as the trapping agent. This same adduct was also obtained when diethyl maleate was used as the alkene. The isomer in which the cyclo-

32 and 33 R 34 R 35 and 36 R

= = =

stable at room temperature but is converted into pyrazoloquinoline 22 upon heating in a sealed tube at 178°C. This transformation can be rationalized in terms of an intramolecular electrocyclization reaction to produce 28 followed by a van Alphen - Huttel rearrangement. The exclusive migration of the phenyl group to the nitrogen atom in this case is probably associated with stabilization of the developing negative charge by the carbomethoxy group in the transition state. Steric factors may also play a role in the migration. Structure 23 also undergoes the loss of nitrogen and the resulting carbene inserts into the carbon-hydrogen bond of benzene to give 25. We also examined the thermal cycloaddition of diazoindene 1with methyl phenylpropiolate in cyclohexane. From the reaction two products were isolated by preparative thick layer chromatography. The major species (34%) corresponded to 1-cyclohexylindene (30). This material is formed by insertion of the carbene derived from diazoindene into the C-H bond of solvent. In addition to 30. the minor component obtained was a white solid whose structure was assigned as methyl pyrazolo[l,5-a]quinoline-2-phenyl-3-carboxylate(31) on the basis of its spectral properties. Here again the formation of 31 can be most conveniently rationalized as arising from a simple 1,3-dipolar cycloaddition followed by a van Alphen - Huttel rearrangement of the initial spiro adduct.

It is of some interest to note that diazoindene 1 is stable under the reaction conditions used for the cycloadditions. This would suggest that the reaction of 1 with electron deficient alkenes does not proceed by initial loss of nitrogen from diazoindene followed by carbene addition to the olefinic T-bond. Instead, the formation of cycloadducts 32-36 can be thought of as resulting from a thermally induced extrusion of nitrogen from intermediate spiro pyrazoline adducts (37) which are formed in a manner analogous to those derived from propiolate cycloadditions. Since the theory of spiroconjugation was formulated over fifteen years ago (50, 5 I), a number of spiroconjugated compounds have been prepared and their spectral data and chemical reactivity have been evaluated. Several dialkyl derivatives of

H; X = COzCH3 X = COzCH3 H; X = NOz

propyl methoxycarbonyl group is syn to the aromatic ring (i.e. 33) has been assigned on the basis of a comparison of resol l appearance ~~ nances due to the ester methoxyls. ~ ~ e c i f i c athe of a high-field signal at 6 2.52 can only be rationalized by assuming a configuration in which shielding due to the anisotropic properties of the aromatic benzene ring is invoked. The isomer to which the arlti configuration has been assigned (i.e. 32) exhibits the same signal at 6 3.63. Because only minimal steric and anisotropic interactions are likely to be incurred with spiro adducts 35 and 36, it is not possible to establish the stereochemistry of substitution on the cyclopropane ring.

spiro[2.4]heptatriene (39) have been experimentally isolated and spectroscopically studied with particular emphasis on the stability of the system (52-54). Spiroconjugation theory suggests that the HOMO level of 39 should be stabilized (50). Using MIND013 calculations, Gordon er al. (54) concluded


PADWA AND GOLDSTEIN

that spiroconjugation adds little, if any, contribution to the stabilization of molecules like 39. On the other hand, Kao and Radom argued that the spiroconjugated stabilization of spiro[2.4]heptatriene is reflected in the calculated strain (55). This comes out to 58.5 kcal/mol, which is less than the sum of the strains of the cyclopropene and cyclopentadiene rings despite the deformed bond angles about the spiro carbon. This result was interpreted as being consistent with a favorable orbital interaction (56). As a continuation of our interest in this area, we decided to study the thermal chemistry of spiroindene 8. Heating a sample of 8 at 160°C gave dimethyl 2aH-cyclopent[c,d]inden-1,2dicarboxylate (40) in good yield. The rate of reaction of 8 is very similar to related cyclopropenes (57) and it does not appear that this molecule is stabilized by spiroconjugation. The rearrangement can be interpreted in terms of an initial ring opening to produce a vinylcarbene intermediate (41) which

undergoes 1,5-electrocyclization followed by a 1,5-sigmatropic hydrogen shift. Other mechanisms are also conceivable and can not be ruled out without further evidence.

ExperimentaP Reaction of diazoindene (1) with dimethyl acetylenedicarboxylate To a solution containing 220 mg of diazoindene 1 in 10 mL of anhydrous benzene was added 250 mg of dimethyl acetylenedicarboxylate. After stirring for 17 h at 25OC, the solvent was removed under reduced pressure and the residue was chromatographed on a silica gel column using a 10% acetone-hexane mixture as the eluent to give 413 mg (94%) of a red oil which was identified as dimethyl Z-diazo1H-inden-1-ylidenebutanedioate (6); ir (neat): 2990, 2100, 1700, 1435, 1340 cm-I; nrnr (CC14,90 MHz) 6: 3.88 (s, 3H), 3.92 (s, 3H), 6.92 (d, lH, J = 6.0 Hz), 6.96 (d, lH, J = 6.0 Hz), and 7.00-7.34 C 63.38, H 4.26, N 9.86; (m, 4H). Anal. calcd. for CI5HIZNZO4: found: C 63.19, H 4.17, N 9.84. A solution containing 400 mg of 6 in 10 rnL of benzene was heated at reflux for 20 min. The solvent was removed under reduced pressure and the residue was chromatographed on a silica gel column using a 10% acetone-hexane mixture to give 256 mg (71%) of a pale yellow solid, mp 86-87"C, whose structure was assigned as dimethyl 3All melting points and boiling points are uncorrected. Elemental analyses were performed by Atlantic Microlabs, Atlanta, GA. The infrared absorption spectra were determined on a Perkin-Elmer 467 infrared spectrophotometer. The ultraviolet absorption spectra were measured with a Cary Model 14 recording spectrophotometer by using 1-cm matched cells. The proton magnetic resonance spectra were determined at 90 MHz by using a Varian EM-390 spectrometer. Mass spectra were determined with Finnegan 4000 mass spectrometer at an ionizing voltage of 70 eV.

a

2511

spiro[2-cyclopropene-l , 1-[l Hlindenel-2,3-dicarboxylate(8); ir (KBr): 3000, 1870, 1730, 1430, 1260, 1050 and 750 cm-'; uv (95% ethanol): 292 (E 1,470), 266 (7,330), and 227 nm (16 660); nrnr (CCl,, 90 MHz) 6: 3.81 (s, 6H), 6.16 (d, IH, J = 7.0 Hz), 6.96 (d, lH, J = 7.0 Hz), and 7.00-7.46 (m, 4H); m/e: 256 (M'), 226, 225, 224 (base), 197, 166, 139, and 138. Annl. calcd. for C15H1204: C 70.30, H 4.72; found: C 70.44, H 4.75.

Reaction of dimethyl spiro[2-cyclopropene-l -l '-[I Hlindenel-2,3-dicarboxylate (8) with diazoindene (1) To a solution containing 26 mg of 8 in 20 mL of benzene was added 30 mg of diazoindene. The solution was heated at reflux for 15 min. At the end of this time the solvent was removed under reduced pressure and the residue was chromatographed on a silica gel column using a 10% acetone-hexane mixture as the eluent. 'The first component isolated contained 55 mg (92%) of a white crystalline solid, mp 137-138"C, whose structure was assigned as dimethyl dispiro[indene-1,4'-[2,3]diazabicycio[3.1.O]hexane-6',1 '-indenel-1' 3'-dicarboxylate (9); ir (KBr): 3020, 1740, 1450, 1430, 1280, 1260, 1190, and 1090 cm-I; uv (95% ethanol): 229 nm (E 26 840); nrnr (CCl,, 90 MHz) 6: 3.06 (s, 3H), 3.96 (s, 3H), 5.69 (d, lH, J = 6.0 Hz), 6.18 (d, lH, J = 6.0 Hz), 7.00 (d, lH, J = 6.0 Hz), 7.03 (d, lH, J = 6.0 Hz), 7.10-7.37 (m, 8H); m/e: 370, 339, 311, 296, 280, and 252 (base). Anal. calcd. for C24H,8N204: C 72.35, H 4.55, N 7.03; found: C 72.06, H 4.73, N 6.98. A solution containing 31 mg of 9 in 20 mL of anhydrous benzene was heated in a sealed tube for 2.5 h at 128OC. The solvent was removed under reduced pressure leaving behind a red oil which was chromatographed on a silica gel column using a 10% acetone-hexane mixture as the eluent to give 26 mg (88%) of an orange oil which was identified as dimethyl bimethyleneindene-1 ,I '-dicarboxylate (11);4 ir (neat): 3100, 3000, 1730, 1600, 1450, 1220, and 750 cm-'; uv (95% ethanol): 355 (E4,320) and 250 nm (14530); nmr (CCL, 90 MHz) 6: 3.73 (s, 3H), 3.76 (s, 3H), 6.20 (d, lH, J = 6.0 Hz), 6.63 (d, lH, J = 6.0Hz),6.80(d, lH, J = 6.0Hz), 6.73-7.26(m,6H),7.33(d, lH, J = 6.0 Hz), 7.70-8.00 (m, lH), and 8.25-8.40 (m, 1H); m/e: 370 (M'), 229, 227, 311, 310, 308, 280, 279, 252, and 125. Anal. calcd. for C24H1803: C 77.82, H 4.90; found: C 77.72, H 4.94. Reaction of dimethyl spiro[2-cyclopropene-1 ,]'-[I Hlindenel-2,3-dicarboxylate (8) with diazomethnne To a solution containing 286 mg of dimethyl spiro[2-cyclopropene1,l '-[I Hlindenel-2,3-dicarboxylate(8) in 20 mL of ether was added an excess of diazomethane. This mixture was allowed to stir for 8 h and the solid that formed was filtered to give 90 mg of a colorless crystalline material, mp 152- 153"C, whose structure was assigned as endo dimethyl spiro[2,3-diazabicyclo[3.1.O]hex-2-ene-6,l '-indenel1,5-dicarboxylate (12); ir (KBr): 3000, 1740, 1430, 1300, 1250, 1200, and 11 10 cm-'; uv (95% ethanol): 236 nm (E 14300) and 220 nm (16 250); nrnr (CDCl,, 90 MHz) 6: 3.76 (s, 3H), 3.85 (s, 3H), 3.98 (d, lH, J = 18.0 Hz), 5.25 (d, lH, J = 7.0 Hz), 5.48 (d, lH, J = 18.0 Hz), 6.93 (d, lH, J = 7.0 Hz), and 7.10-7.56 (m, 4H). Anal. calcd. for CI6Hl4O4N2: C 64.42, H 4.73, N 9.39; found: C 64.52, H 4.71, N 9.20. Thermolysis of dimethyl spiro[2,3-diaznbicyc10[3.1.O]hex-2-ene6,l'-indenel-1,5-dicarboxylate (12) in benzene A solution containing 80 mg of 12 in 25 mL of anhydrous benzene was heated in a sealed tube at 110°C for 10 min. The solvent was removed under reduced pressure and the residue was chromatographed on a silica gel column using a 10% acetone-hexane mixture as the eluent. ~ h ;first material 6 be eluted from the column contained 443 mg of a pale yellow oil whose structure was assigned as exodimethyl spiro[2,3-diazabicyc10[3.1.O]hex-2-ene-6,1'-indene]-1,5dicarboxylate (13); ir (neat: 2990, 1730, 1530, 1450, 1430, 1260, 1120, and 780 cm-'; uv (95% ethanol): 242 (E 14420) and 215 nm (22 050); nrnr (CC14,90 MHz) 6: 3.73 (s, 3H), 3.87 (s, 3H), 5.13 (d, lH, J = 18.0 Hz), 5.47 (d, lH, J = 18.0 Hz), 6.20 (d, lH, J = 7.0 4The sterochemistry of 11 is plausible but not proven.


25 12

CAN. J. CHEM. VOL. 6 2 , 1984

Hz), 6.60-7.30 (m, 5H); m/e: 298 (M+), 270, 21 1, 210, and 152. Anal. calcd. for C16Hl,Nz0,: C 64.42, H 4.73, N 9.39; found: C 64.40, H 4.75, N 9.30. A solution containing 100 mg of 12 in 10 mL of benzene was also heated in a sealed tube at 145°C for 35 min. The solvent was removed under reduced pressure and the residue was chromatographed on a medium pressure chromatography column using a 10% acetonehexane mixture as the eluent. The first fraction contained 80 mg of a yellow oil whose structure was assigned as I-(methyl diazoacetate)I-(methyl ethylene-I-acetate)indene (14); ir (neat): 3400, 2130, 1720, 1440, 1315, 1210, 1180, 1130, and 860 cm-I; uv (95% ethanol): 250 (E 11 030) and 210 nm (26 530); nrnr (CCI,, 90 MHz) 6: 3.70 (s, 3H), 3.76 (s, 3H), 5.70 (s, IH), 6.03 (s, IH), 6.73 (d, lH, J = 5.0 Hz), 6.83 (d, IH, J = 5.0 Hz), 7.06-7.33 (m, 3H), and 7.60-7.77 (m, IH); m/e: 270, 212, 180, 179, 168, 167, 146 (base), and 145. Anal. calcd. for CI6Hl4O4N2: C 64.42, H 4.73, N 9.39; found: C 64.62, H 4.78. N 9.16. Reaction of dimethyl spiro[2-cyclopropene-1-/'-[I Hlindenel-2,3-dicarboxylate (8) with diazopropane To a solution containing 40 mg of 8 in 20 mL of anhydrous ether at 0°C was slowly added an ether solution of diazopropane until the orange color persisted. The mixture was allowed to stir for 12 h and the solvent was removed under reduced pressure. The residue was chromatographed on a silica gel column using a 10% acetone-hexane mixture as the eluent. The major fraction contained 51 mg (98%) of a white crystalline solid, mp 114- 115"C, whose structure was assigned as dimethyl spiro[2,3-diazo-4,4-dimethylbicyclo[3.1 .O]hex-2ene-6,l '-[I H]indene]- l,5-dicarboxylate (16); ir (KBr): 3000, 1740, 1450, 1430, 1270, 1240, 1200, and 1080 cm-I; uv (95% ethanol): 232 nm (E 19010);nmr (CCI,, 90 MHz) 6: 1.33 (s, 3H), 1.60 (s, 3H), 3.62 (s, 3H),3.83 (s, 3H), 5.49(d, I H , J = 6.0Hz), 6.90(d, l H , J = 6.0 Hz), and 7.10-7.40 (m, 4H). Anal. calcd. for CIBH18N204: C 66.24, H 5.56, N 8.58; found: C 66.18, H 5.63, N 8.31. Thermal rearrangement of climethy1spiro[2-cyclopropene-I. 1'-[I HIindenel-2,3-dicarbo.rylate(8) in benzene A solution containing 60 mg of 8 in 100 mL of anhydrous benzene was heated in a sealed tube at 176OC for 30 min. The solvent was removed under reduced pressure and the residue was chromatographed by hplc on a Zorbax-Cn preparative column using a 3% acetonehexane mixture. The major component contained 28 mg of a yellow oil whose structure was assigned as dimethyl 2aH-cyclopent[c,d]inden-1,2-dicarboxylate (40); ir (neat): 2990, 1720, 1700, 1430, 1280, 1100, 900, 770, and 720 cm-I; uv (95% ethanol): 320 (E 4,100), 275 (6,160), 245 (8,210), 238 (8,360), and 215 nm (10560); nmr (CCI,, 90 MHz) 6: 3.69 (s, 3H), 3.83 (s, 3H), 5.18 (s, IH), 6.75 (d, IH, J = 5.5 Hz), and 7.15-7.46 (m, 4H); m/e: 256 (M+), 241, C 70.30, H 4.72; found: C 225, and 166. Anal. calcd. for CI5Hl2O4: 70.15, H 4.69. Reaction of dimethyl spiro[2-cyclopropene-1,l-[I H]indene]2,3-clicarboxylate (8) with chloroacetaldoxit~ze To a solution containing 200 mg of 8 and 80 mg of a-chloroacetaldoxime and 20 mL of anhydrous ether at 0°C was slowly added 100 mg of triethylamine. The mixture was stirred at O°C for 1 h and the solution was filtered in order to remove the triethylamine hydrochloride salt. The solvent was removed under reduced pressure, leaving behind 240 mg of a pale yellow oil which was I .O]hexidentified as dimethyl spiro[4-methyl-2-oxa-3-azabicyclo[3. 3-ene-6,l '-indenel-l,5-dicarboxylate (17); ir (neat): 3000, 1760, 1450, 1390, 1280, 1240, 1210, 1 1 10, 1090,940, 870, and 750 cm-I; uv (95% ethanol): 247 (E 13770) and 210 nm (14910); nmr (CCI,, 90 MHz) 6: 2.03 (s, 3H), 3.70 (s, 6H), 5.80 (d, 1 H, J = 6.0 Hz), 6.90 (d, IH, J = 6.0 Hz), and 6.98-7.23 (m, 4H); I3C nmr (CDC13, 30 MHz) 6: 12.28 (q), 42.80 (s), 53.16 (q), 58.54 (s), 79.10 (s), 122.31 (d), 124.87 (d), 125.19 (d), 127.68 (d), 129.29 (d), 134.75 (d), 137.00 (s), 145.27 (s), 157.32 (s), and 162.70 (s); mle: 272, 213 C 65.17, H 4.82, (base), 154 and 114. Anal, calcd. for C17HISN05: N 4.47; found: C 65.09, H 4.76, N 4.53. Chromatography of this material on a silica gel column using a 10%

acetone-hexane mixture as the eluent resulted in an epimerization reaction to give endo-dimethyl spirol4-methyl-2-oxa-3-azabicyclo13.1.01-hex-3-ene-6,I '-indenel-1,5-dicarboxyate (18); ir (neat): 3000, 1750, 1440, 1380, 1280, 1240, 1110, 870, and 730 cm-I; uv (95% ethanol): 242 (E 1 1 050) and 221 nm (10730); nrnr (CCI,, 90 MHz) 6: 2.1 (s, 3H), 3.80 (s, 3H), 3.83 (s, 3H), 6.57 (d, IH, J = 6.0 Hz), 6.83 (d, IH, J = 6.0 HZ), and 7.00-7.45 (m, 4H); I'c nrnr (CDCI,, 20 MHz) 6: 12.46 (q), 40.26 (s), 53.40 (q), 58.87 (s), 84.49 (s), 122.31 (d), 122.72 (dl, 125.50 (d), 128.18 (d), 131.18 (d), 132.27 (d), 136.12(s), 145.51 (s), 154.67 (s), 163.51 (s), and 164.72 (s); m/e: 272, 213 (base), 154, and 114. Atzal. calcd. for CI7Hl5NO5: C65.17, H 4 . 8 2 , N 4 . 4 7 ; f o u n d : C 6 5 . 1 0 , H4.68, N4.31. A solution containing 100 mg of 17 (or 18) in I0 mL of anhydrous benzene was heated at 160°C for 10 min. The solvent was removed under reduced pressure leaving behind a pale oil whose structure was assigned as pyruvate 20;' ir (neat): 3000, 1730, 1700, 1600, 1450, 1380, 1310, 1240, 1150, 1050, and 750 cm-I; uv (95% ethanol): 245 (E5,900) and 247 nm (16550); nmr (CC14, 90 MHz) 6: 3.83 (s, 3H), 3 . 8 7 ( ~ , 3 H ) , 6 . 8 7 ( dI,H , J = 6 . 0 H z ) , 7.00-7.20(m,4H),and7.35 (d, IH, J = 6.0 Hz); '" nrnr (CDCI2, 20 MHz) 6: 52.77 (q), 53.61 (q), 126.31 (s), 126.88 (d), 127.04(d), 127.44(s), 131.36(d), 131.78 (d), 133.30 (s), 140.37 (d), 141.32 (d), 144.54 (s), 152.89 (d), 154.25 (d), 182.92 (s), and 185.15 (s); m/e: 272 (M+),213 (base), 154, and C 66.17, H 4.44; found: C 66.03, H 114. Anal. calcd. for CI5Hl205: 4.27. Reaction of diazoindetle (1)with tnethyl propiolate To a solution containing 200 mg of diazoindene 1 in 20 mL of anhydrous benzene was added 200 mg of methyl propiolate. The mixture was allowed to stir at 25OC for 18 h and the red solution was filtered to give 75 mg of a white crystalline material, mp 254-255"C, whose structure was assigned as methyl-IH-benz[e]indazole-3carboxylate (21); ir (KBr): 3250, 1730, 1470, 1440, 1270, 1220, 1060, 1020, 980, 820, and 760 cm-I; uv (95% ethanol): 133 (E 6,340), 317 (6,890), 292 (12410), 281 (12690). 270 (15720), 255 (17 930), 237 (48 000). and 230 nm (41 380); nrnr (C5D6,90 MHz) 6: 4.0(s, 3H),7.63-7.80(m, 3H), 8.10-8.30(m,2H), 8.45-8.65(m, IH), and 14.5 (s, IH); m/e: 266 (M+), 195, 140, and 138 (base). Anal. calcd. for Cl,Hl,N202: C 69.01, H 4.46, N 12.38; found: C 69.21, H 4.47, N 12.40. The solvent was removed from the mother liquor and the residue was chromatographed on a medium pressure silica gel column using a 5% acetone-hexane mixture as the eluent. The major diazo compound isolated from the column (120 mg) was assigned the structure of methyl (Z)-diazo-1H-inden-I-ylidenepropanoate(24) on the basis of its spectral data; ir (neat): 3300, 21 10, 1720, 1620, 1440, 1400, 1310, 1250, 1220, and 1100 cm-I; uv (95% ethanol): 363 (E 15 790), 298 (12680), 287 (12620), 252 (14660), 245 (14 150) and 210 nm (28990); nmr (CCI,, 90 MHz) 6: 3.83 (s, 3H), 6.56 (d, IH, J = 6.0 Hz),6.66(s, lH),6.86(s, l H , J = 6.0Hz),7.00-7.33(m,3H),and 7.46-7.66 (m, IH). A solution containing 150 mg of the above oil in 10 mL of benzene was heated in a sealed tube at 178OC for 12 h. The solvent was removed under reduced pressure and the residue was chromatographed to give 135 mg of methyl spiro[3a,7a-dihydroindene-I, l '-indenel-3carboxylate (26); ir (neat: 2990,2900, 1720, 1620, 1440, 1330, 1230, 11 10, 1090, and 960 cm-'; uv (95% ethanol): 258 (E 1 1 240) and 218 nm (27 720); nmr (CCI.,, 90 MHz) 6: 3.45 (dd, lH, J = 12.0, J = 5.0 Hz), 3.72(s,3H),4.11(brd, I H , J = 12.0Hz),5.10-5.26(m, IH), 5.66-5.86 (m, 3H), 6.16 (d, IH, J = 6.0 Hz), 6.22 (brs, IH), 6.58 (d, IH, J = 6.0 Hz), and 7.00-7.30 (m, 4H); '-'C nrnr (CDCI,, 20 MHz) 6: 43.83 (d), 44.86 (d), 51.54 (q), 70.96 (s), 121.16 (d), 121.72 (d), 122.47 (d), 123.01 (d), 124.22 (d), 125.51 (d), 127.45 (d), 131.10(d), 139.64(d), 139.87 (s), 144.29(s), 147.50(d), 148.87 (s), C ~82.58, : H 5.84; found: C 164.69 (s). Anal. calcd. for C I P H I ~ O 82.20, H 5.80. The next component isolated from the chromatography of the resi'The stereochemistry of 20 is unknown.


PADWA AND

due derived from diazoindene with methyl propiolate contained 26 mg of methyl pyrazolo[l,5-alquinolinc-3-carboxylate (22): ir (neat): 1710, 1540. 1450, 1380, 1320. 1280, 1220, 1200, 1170. 1100, 800, and 770 cm-I; uv (95% ethanol): 335 (E 8.500). 320 (6.860). 265 (294l0), 258 (28 100). and 208 (25 000); nrnr (CCIa,90 MHz) 6: 3.90 (s, 3H), 7.1 (d, IH, J = 7.0 Hz), 7.60-7.80 (m, 3H), 8.25 (d, IH, J = 7.0 Hz), 8.33 (s, IH), and 9.80-9.93 (ni. IH); tnlp: 226 (M'), 195 (base). 167. 14 1 . and 180. Anal. calcd. for Cl1Hl0N2O2: C 69.0 1 , H 4.46, N 12.38; found: C 68.87, H 4.31. N 12.46. The third component isolatcd from the column contained a mixture of isomeric diazo compounds (23, Z and E ) which could not be separated. A solution containing 80 mg of this oil in I0 mL of benzene was heated at 178°C for I0 min. Removal of the solvent left a yellow oil which was chrornatographed on a silica gel column to give 55 mg of methyl P-benzylindenylindene-P-carboxylate (25)": ir (neat): 3090. 2980, 1720. 1460. 1440, 1240. 1040, and 760 cm..'; uv (95% ethanol): 310 (E 4.090) and 250 nm (20460); nrm (CCIJ, 90 MHz) 6: 3.16 (brs, 2H), 3.70 (s, 3H), 5.8-6.4 (2H), 7.00-7.50 (m, 9H), "C nmr (CDCI,, 20 MHz) 6: 39.16 ( t ) , 52.36 (q). 119.17 (d), 123.89 (d), 125.25 (d), 126.31 (d), 127.80 (d), 128.51 (d), 128.39 (d), 132.01 (d), 134.85 (s), 144.20 (s), and 168.05 (s); tnlr: 276 (M'), 245, 2 17 (base), and 215. Anal. calcd. for ClllHbo2:C 82.58, H 5.84; found: C 82.70, H 5.83. In addition, 25 mg of pyrazoloquinoline 22 was also isolated. Reoctiotl of diazoitzrlene with methyl phr~zylpropiolate To a solution containing 100 mg of diazoindene (1) in 10 mL of anhydrous cyclohexane was added 124 mg of methyl phenylpropiolate. The mixture was heated in a sealed tube at 160°C for I h. At the end of this time the solvent was removed under reduced pressure and the residual oil was chrornatographed on a medium pressure chromatography column using a 10% acetone-hexane mixture as the eluent. The first compound isolated from the column contained 65 mg of a pale yellow oil which was identified as I-cyclohexylindene (30); ir (neat): 3070, 2930, 2860, 1460, 1450, 800. 760, 750, and 720 cm-I; nmr (CCIJ, 90 MHz) 6: 0.53-2.20 (m. 1 IH), 3.25-3.40 (m, IH), 6.40 (dd. lH, J = 6.0, J = 1.5 Hz), 6.20 (dd, 1H, J = 6.0, J = 2.0 Hz), and 6.90-7.43 (m, 4H); tnle: 198 (M'). 116 (base), 115, and 83. Anal. calcd. for CI5Hln:C 90.85, H 9.15; found: C 90.81, H 9.10. The next compound isolated from the column contained 30 mg of a white solid, mp 109- l 10°C, whose structure was assigned as methyl pyrazolo[l,5-o]quinoline-2-phenyl-3-carboxylate (31); ir: 1370, 1330, 1160, and I I I0 cm-'; uv (95% ethanol): 337 (E 6,400), 321 (5,700), and 265 nm (40515); nmr (CCI,, 90 MHz) 6: 3.70 (s, 3H), 6.93 (d, IH, J = 8.0 Hz), 7.20-7.63 (m, 8H), 8.16 (d, IH, J = 8.0 Hz), and 9.10-9.30 (m, 1H); mle: 302 (M'), 27 1 (base), 244, 243, and 140. Anal. calcd. for ClsH14N20z: C 75.48, H 4.67, N 9.27; found: C 75.36, H 4.72, N 9.20. Reaction of diozoit~denewith methyl ocrylate To a 100-mg sample of diazoindene (1) was added 129 mg of methyl acrylate. After stirring for 6 h at 25'C, the reaction mixture was chrornatographed on a medium pressure column using a 5% acetone-hexane mixture as the eluent. The first compound isolated contained 88 mg (63%) of a colorless oil whose structure was assigned as methyl cis-spiro(cyclopropane-I,I1-11Hlindenel-2-carboxylate (32); ir (neat): 3050, 2975, 1740, 1460, 1440, 1390, 1320, 1280, 1180, 1090, 1070, 1000, 960, 940, 850, and 820 cm--'; uv (95% ethanol): 290 (E960), 272 (1,330). 245 (5,790), and 227 nm (26060); nmr (CCI,, 90 MHz) 6: 1.80 (dd, l H, J = 8.5 Hz, J = 5.5 Hz), 2.23 (dd, I H , J = 6.5 Hz, J = 5.5 Hz),2.60(dd, 1 H , J = 8.5 H z , J = 6.5 Hz), 3.63 (s, 3H), 6.53 (d, I H , J = 6 . 0 H z ) . 6.83(d, 1H, J = 6.0 Hz), and 6.90-7.40 (m, 4H); "C nmr (CDCI?,20 MHz) 6: 19.37 (t), 28.46 (d), 40.20 (s), 51.68 (qd), 117.45 (d), 121.45 (d), 124.61 (d), 135.36 (d). 143.47 (s), 145.56 (s), and 171.82 (s); mle: 200 (M'), 185, 169, 168, 141 (base), 128, and 115. Anal. calcd. for "The stereochemistry of compounds 23-25 is unknown.

(

CI3Hl2O2: C 77.98, H 6.04; found: C 77.82. H 6.09. Thc next componcnt isolatcd from the column contained 48 mg (32%) of a colorless oil whose structure was assigned as methyl trrrns-spirolcyclopropane- I . I '-1 I H lindenel-2-carboxylate (33); ir (neat): 3100,3000. 1730. 1400. 1390, 1360, 1280, I2 10. 1 170, 1090, 1020. 940, 840, 810. 760. and 720 c m - ' ; uv (95% ethanol): 300 (E 1,500). 290 ( I ,880). 263 (5,640). and 230 nm (21 430); nmr (CC14, 90 MHz) 6: 1.80 (dd, IH, J = 8.5 Hz, J = 4.5 Hz), 2.19 (dd, lH, J = 7.5 Hz, J = 4 . 5 Hz),2.60(dd, 1 H . J = 8.5 H z , J = 7.5Hz), 2.52(s, 3 H ) , 5 . 8 9 ( d , IH, J = 5.7 H z ) , 6 . 7 8 ( d , 1 H . J = 5.7Hz), and 6.97-7.48 (m. 4H); "C nmr (CDCI,. 20 MHz) 6: 17.66 (t), 27.76 (d), 40.21 (s). 51.26 (q), 121.35 (d). 121.45 (d). 124.57 (d), 126.28 (d), 130.00 (d), 139.07 (d), 142.20 (s), 144.44 (s), and 169.90 (s); mle: 200 (M'), 169, 168. and 115 (base). Ancll. calcd. for C13H1202: C 77.98. H 6.04; found: C 77.73, H 6.09. Reaction of rliazoitzrlet~ewith tlierlzy/firt~z~r~'r~tc~ To a solution containing 200 mg of diazoindene in 10 mL of anhydrous benzene was added 240 mg of diethylfumarate. After stirring for 53 h at 25"C, the solvent was removed under reduced pressure and the resulting residue was chromatographed on a silica gel column using a IYo acetone-hexane solution as the eluent. The first compound isolated from the column contained 320 mg (82%) of a white solid. mp 91 -92"C, whose structure was assigned as diethyl trans-spiro[cyclopropane-l. l '-indenel-2.3-dicarboxylate (34); ir (KBr): 3010, 1730, 1450, 1370, 1330, 1310, 1280, 1210, 1160. 1080, 1020, and 850 cm-'; uv (95% ethanol): 295 (E 1.420), 260 (2,960)- and 232 nm (25 800); nmr (CCIJ, 90 MHz) 6: 1.15 (t, 3H, J = 6.0 Hz), 1.23 (t, 3 H , J = 6.0Hz). 3.25 (s, 2H),4.07 ( q , 2 H , J = 6 . 0 H z ) , 4.16(q, 2H, J = 6.0 Hz), 6.46 (d, 1H, J = 6 Hz), 6.83 (d, IH, J = 6.0 Hz), and7.00-7.52 (m, 4H);tnle: 286(M'), 241,240,213, 168, and 139 (base). Anal. calcd. for C,7HlHO14:C 71.31, H 6.34; found: C 71.21, H 6.28. Reaction of' diazoitldetle with t~itroetltyletze To a solution containing 215 mg of diazoindene in 10 mL of benzene was added 200 mg of nitroethylene. After stirring for 4 h the solvent was removed under reduced pressure and the residue was chrornatographed on a medium pressure chromatography column using a I% acetone-hexane solution as the eluent. The first component contained 169 mg (67%) of a colorless oil whose structure was assigned as 2-nitrospiro[cyclopropane-I , l '-[I Hlindene] (35); ir (neat): 3230, 1560, 1460, 1420, 1370, 1220, 1090, 1080, 1000, 960, 880, 820, and 740 cm-.I; uv (95% ethanol): 298 (E 1,990) and 242 nm (17 340); nmr (CCI,, 90 MHz) 6: 2.00 (t, lH. J = 6 Hz), 2.86 (t, IH, J = 6 H z ) , 4 . 9 3 (brd. IH, J = 6 H z ) , 6 . 4 5 (d, IH, J = 5.7Hz), 6.80-7.45 (m, 5H); tnle: 187 (M'), 158, 144, 141, 139 (base), 128, and 115. Anal. calcd. for C1IH,NO2:C 70.58, H 4.85, N 7.48; found: C 70.35, H 4.87, N 7.33. The second component to be eluted from the column contained 70 mg (28%) of a colorless oil whose structure was assigned as the isomeric 2-nitro-spirolcyclopropane- I, 1 [I Hlindene] (36); ir (neat): 3040, 1560, 1470, 1430, 1370, 1210, 1 100, 960, 860, 820, and 770 cm-'; uv (95% ethanol): 301 (E 2,190) and 246 nm (1 1700); nmr (CCI,, 90 MHz) 6: 2.01 (dt, 1H, J = 6.5 Hz. J = 2.0 Hz), 2.63 (dt, l H , J = 6 . 5 H z , J = 2 . 0 H z ) , 4 . 8 3 ( b r t , lH,J=6.5Hz),5.80(brd, l H , J = 6.5Hz),6.82(d, l H , J = 6 . 5 H z ) , a n d 7 . 0 0 - 7 . 4 0 ( m , 4 H ) ; mle: 187 (M'), 158, 141 (base), and I 15. Anal. calcd. for C, ,HgN02: C 70.58, H 4.85, N 7.48; found: C 70.30, H 4.86. N 7.33.

Acknowledgments We wish to thank the National lnstitute of Health for generous support of this work. A.P. also wishes to thank the organic faculty at the University of Wurzburg for their gracious hospitality during his stay at the lnstitute as an Alexander von Humboldt Senior Awardee. Use of the high field nmr spectrometer used in these studies was made possible through a NSF equipment grant.


2514

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1984

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