The addition of NH3 and other primary amines to Z-3-phenyl-2-(arylsulfonyl)propenoyl chlorides
gives trans-2-arylsulfonyl-3-phenyl-2-azetidinones as the major product in addition to the corresponding 2-arylsulfonyl-3-phenylpropenamide. Electron-withdrawing substituents in the arylsulfonyl group increased the percentage of products derived from 1,4-addition relative to 1,2-addition,
while electron-donating substituents increased the amount of 1,2-addition observed in the product
mixture. Addition of α-methylbenzylamine gave a 68:32 mixture of the two diastereomers of the
trans-azetidinone. The major diastereomer was identified as the 1-(1R)-(3S,4S) and 1-(1S)-(3R,4R)
enantiomers 16a by single-crystal X-ray crystallographic analysis. Phenylthio and phenylsulfoxo
substituents did not promote 1,4-addition, although the addition of ammonia to Z-3-phenyl-2-(phenylsulfoxo)propenoyl chloride (7a) gave a 95:5 ratio of the corresponding propenamide 8a and
a 3-(phenylsulfoxo)azetidinone 9a. trans-4-Phenyl-3-(arylsulfonyl)-2-azetidinones 12a and 12c were
sulfonated by the pyridine−SO3 complex to give the corresponding N-sulfonates 28 in >80% yield.
The p-methoxybenzyl substituent of 15 was removed by ceric ammonium nitrate in CH3CN to give
12a in 70% yield.
Soluble, Infrared-Absorbing Croconate Dyes from 2,6-Di-tert-butyl-4-methylchalcogenopyrylium Salts -The higher analogues of known pyrylium dye (Ia) are investigated.-(SIMARD, TODD P.; YU, JIAN H.; ZEBROWSKI-YOUNG, JENNIFER M.; HALEY, NEIL F.; DETTY, MICHAEL R.; J.
Activated Michael Acceptors as Precursors to Heterocycles. Part 1.2-Azetidinones from 2-(Arylsulfonyl)propenoyl Chlorides and Amines.-Azetidinones (II), (VII), and (IX) are formed as major or exclusive 1,4-addition products in the reaction of ammonia and primary amines with sulfonyl compounds (I). Fluorine as electron-withdrawing substituent in the arylsulfonyl group increases the ratio of azetidine to amide products. The addition of prochiral amine (VIII) to compound (Ia) gives a 68:32 mixture of diastereomers with main isomer (IX). Azetidinones (IIa), (IIc), and (VIIc) are examined in sulfonation and deprotection reactions. Phenylthio and phenylsulfoxo substituents as in compounds (X) and (XII) do not promote the formation of azetidinones. -(ZHOU, F.; ROSEN, J.; ZEBROWSKI-YOUNG, J. M.; FREIHAMMER, P. M.; DETTY, M. R.; LACHICOTTE, R.
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