Compound VII Research Articles

Sur la pyrolyse d'α-acétoxy cétones. Pyrolyse du tétraacétyl-7,12,15,32 nor-16 glaucanol

The pyrolysis of 7,12,15,32-tetraacetyl 16-nor glaucanol IVb (a degradation product of glaucarubin) leads to the olefin 7,15, 32-triacetyl 11, 16 -bis nor glaucanol VII which has a contracted ring C. A mechanism is proposed for the formation of compound VII.

The reaction of methyl propiolate with 2‐aminopyridines

AbstractThe structure (III) reported by Lappin (2) for the diadducts formed by the reaction of methyl propiolate with 2‐aminopyridines has been found to be incorrect. The correct structure (IV) has been proven by spectral studies and cyclisation to compound VII. In two cases new compounds having structures of the type (III) have been isolated. N.M.R. data are reported for all products.

Hydroformylation of glycals

Hydroformylation of 3,4-di-O-acetyl-d-xylal gave 4,5-di-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-lyxo-hexose (I) and 4,5,di-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-xylo-hexose (II). Methyl sulfoxide oxidation of 2,3-di-O-acetyl-1,5-anhydro-4-deoxy-d-arabino-hexitol (III) and of 2,3-di-O-acetyl-1,5-anhydro-l-xylo-hexitol (IV) yielded compounds I and II, respectively.Reaction of 3,4,6-tri-O-acetyl-d-glucal with carbon monoxide and hydrogen under carefully controlled conditions yielded 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-manno-heptose (VII) and 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-aldehydo-d-gluco-heptose (VIII) in a 70% yield. Compound VII was readily separated from the mixture of aldoses and alditols by column chromatography. Alternatively, aldoses VII and VIII were separated via their 2,4-dinitrophenylhydrazones. The conversion of aldoses VII and VIII into their diethyl dithioacetal derivatives is also described.The formyl group located in an equatorial orientation was found to be reduced at a faster rate than its axial counterpart.

Reaction of thioxanthylium perchlorate with diazomethane

AbstractThe reaction of thioxanthylium perchlorate with diazomethane was investigated. Depending on the reaction conditions, seven compounds (II, III, V, VI, VIII, IX, and X) are formed which were identified on the basis of spectral data (mainly mass spectra) and chemical reactions. A synthesis was worked out (reaction of compound VII with boron trifluoride) in which dibenzo[b,f]thiepine (VIII) is formed as major product (55%).

Jervine—XV : Hydrogenation of the 13,17a-double bond

The α,β-unsaturated ketone XIa, produced from N-acetyl-tetrahydroisojervine (Xa) by alkali-catalyzed double bond shift, gave on catalytic hydrogenation with platinum in acetic acid and subsequent acetylation the 13β,17aα-dihydro compound VII rather than the product of cis(α, α)-hydrogen addition, VIIb, which is the more stable member of this pair of 13-epimers (VIII VII). 6 The formation of VIII as the kinetically favoured product is explained by the predominance of stereoelectronic over purely steric control of proton addition at C-13 in the re-ketonization of an enolic intermediate arising by 1,4-addition of hydrogen to the enone system of XIa. The observation 1 that the hydrogenation of jervine (Ia) under these conditions affords (in poor yield) tetrahydrojervine (IIIa) by cis(α, α)-addition has been confirmed. With O,N-diacetyljervine (Ib), however, the primary event is the hydrogenolysis of the 17,23-ether linkage resulting in the establishment of a free 23-hydroxyl group. This may be accompanied by de-conjugation of the enone grouping (leading to 3,N-diacetyl-tetrahydroisojervine, isolated as the triacetate Xb), or followed by hydrogenation of the double bond (leading by trans(13β,17aα)-addition to the 3,N-diacetate of compound IX, and to a configurationally as yet undefined new stereoisomer (XII) of the latter). These results are discussed in terms of their dependence of the ease of protonation of the 17,23-ether oxygen, and the direction of polarization of the enone system before and after cleavage of the 17-oxygen bond.

DIRECT CARBONYLATION OF THE BENZOPHENONE SEMICARBAZONES AND BENZOPHENONE AZINE USING DICOBALT OCTACARBONYL

Benzophenone semicarbazone (I) reacted with carbon monoxide at about 4000 p.s.i. and at 235–245° in the presence of preformed dicobalt octacarbonyl as catalyst to yield 3-phenyl-phthalimidine (II), 3-phenyl-2- (N benzhydrylcarboxamido)phthalimidine (V), N,N′-dibenzhydrylurea (VI), and N-benzhydrylurea (VII). At 200–220° substance I gave compound VII, benzophenone azine (VIII), and benzophenone 4-benzhydrylsemicarbazone (IX). When the reaction temperature was further reduced to 175–185°, compound I did not produce the carbonylation product obtained in the second experiment but only the degradation and reduction products VIII, and IX, respectively. Carbonylation of benzophenone azine at 235–245° produced 3-phenylphthalimidine, whereas that of benzophenone 4-benzhydrylsemicarbazone at the same temperature yielded 3-phenylphthalimidine and 3-phenyl-2-(N-benzhydrylcarboxamido) phthalimidine. Independent syntheses of the last compound and of benzophenone 4-benzhydrylsemicarbazone are described.

Δ 2,6-Hexalin-1,5-dione

Δ 2,6-Hexalin-1,5-dione (I) has been prepared from decalin-1,5-dione (III) as follows. The latter substance was converted to the diketal IX(R 1  R 2  H) which, on bromination with phenyl-trimethylammonium tribromide in tetrahydrofuran, was transformed into the 2,6-dibromo compound IX(R 1  R 2  Br). Treatment with potassium t-butoxide in t-butyl alcohol gave the diene diketal X, and this substance on mild acid hydrolysis was converted into the highly crystalline diene dione I. Δ 2-Octalone 1 (VI) has similarly been prepared from the ketal VII(R  H) of α-decalone via the bromo compound VII(R  Br) and the unsaturated ketal VIII. The product was identical with material prepared by the pyrolysis of 2-acetoxy-1-decalone (V).

Chemistry of acetylenic ethers XXXV. Reactions of alkali metal derivatives of ethoxyethyne and of ethylthioethyne with epichlorohydrin

AbstractThe reaction between epichlorohydrin and ethylthioethynyl‐lithium affords the enynol V and furfuryl ethyl sulphide VI. The same reaction with ethoxyethynyl‐lithium, however, produces the epoxy compound VII.