The preparation and thermal decomposition of selected pyrazolines
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Abstract
The reaction of diazoalkanes with a,p-unsaturated esters, amides, nitriles, ketones, and nitro compounds is known to furnish negatively substituted pyrazolines. When the alpha carbon atom of the a,p-unsaturated compound is bonded to a group other than hydrogen the delta- or azo type pyrazoline is obtained. The primary objective of the present work was the extension of this synthetic method to the preparation of new types of 61- pyrazolines which would posses certain desired structural features. In particular it "'as of interest to prepare a series of negatively substituted 61-pyrazolines having centers of unsaturation in the substituent groups, and to synthesize a number of negatively substituted dipyrazolines.
The selective addition of one equivalent of diazomethane to diolefinic esters, which had one activated and one unactivated double bond, was realized. This high yield process made available a new series of pyrazolines having unsaturation in substituent groups. Among the compounds prepared were: vinyl 3-methyl-61-pyrazoline-3-carboxylate, allyl 3- methyl-61-pyrazoline-3-carboxylate, allyl 3,4-dimethyl-61- pyrazoline-3-carboxylate, vinyl 3,4-dimethyl-61-pyrazoline-3- carboxylate, vinyl 4-methyl-62-pyrazoline-3-carboxylate, methyl 4-phenyl-5-allyl-62-pyrazoline-5-carboxylate, and 4-phenyl- 5-allyl-6 2-pyrazoline-5-carboxylic acid. [TRUNCATED]
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Thesis (Ph.D.)--Boston University
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