Synthesis of 1,1-difluoro-5-(1H-9-purinyl)-2-pentenylphosphonic acids and the related methano analogues. Remarkable effect of the nucleobases and the cyclopropane rings on inhibitory activity toward purine nucleoside phosphorylase
摘要:
A series of 1,1-difluoro-5-(1H-9-purinyl)-2-pentenylphosphonic acids, (E)-2a,b and (Z)-2a,b, as well as the related methano analogues (+/-)-3a,b and (+/-)-4a,b were prepared for evaluation of their PNP inhibitory activities. The cyclopopane ring and the hypoxanthine residue were found to increase the profile of inhibitory activity. The IC50 and K-i values of difluoro({1R*,2S*)-2-[2-(6-oxo-6,9-dihydro-1H-9-purinyl)ethyl]cyclopropyl)methylphosphonic acid (+/-)3b toward PNP purified from Cellulomonas sp. were determined to be 70 nM and 8.8 nM, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.
Stereoselective Synthesis of 1,4-Dienes. Application to the Preparation of Insect Pheromones (3Z,6Z)-Dodeca-3,6-dien-1-ol and (4E,7Z)-Trideca-4,7-dienyl Acetate
摘要:
Stereoselective synthesis of Z,E and Z,Z-1,4-dienes has been achieved by the cross-coupling of allylic substrates with vinyl organometallic reagents. Key to this strategy was the development of a method for regiospecific incorporation of a tri-n-butylstannyl group in the gamma-position of the allylic cross-coupling partner. The steric bulk of this moiety ensures the stereochemical integrity of the allylic double bond throughout the coupling sequence and is easily replaced by hydrogen in the coupled product. This strategy has been applied to the synthesis of the termite trail marker pheromone 22 and the leafminer moth sex pheromone 28.