ChemInform Abstract: Substituted Ethynylphosphonates and Their Anticholinesterase Activity.

Abstract

ChemInform Abstract The alkynylphoshonates (III) and the saturated derivatives (VII) and (XI) are prepared by common methods. The ethynyl compounds have moderate anticholinesterase activity.

Dialkyl 1-Alkynylphosphonates: a Range of Promising Reagents

“…These compounds were readily obtained from dialkyl or diphenyl chlorophosphates and the appropriate terminal alkynylmagnesium bromide, which was prepared in turn from the alkyne 21 and ethylmagnesium bromide in Et 2 O or THF (Scheme 9). [56] The most widely employed phosphorus reagent is diethyl chlorophosphate 19 (R = Et) which is reacted with the alkynylmagnesium bromide through direct [33,34,57] or inverse [56] addition at 0°C in Et 2 O or at -30°C in THF. This procedure has been successfully employed for the preparation of a variety of dialkyl 1-alkynylphosphonates 3 in fair to good yields (51 to 76%), with the best results generally obtained using addition of the alkyne salt to the chlorophosphate.…”

“…Thus, sodium diethylphosphite 12 reacts with 1-bromoalkynes 2 in THF at low temperature to give diethyl 1-alkynylphosphonates 13 in fair to good yields (37-75%) (Scheme 6). [32,33,34] Usually, yields are improved upon further lowering the temperature and adding the bromoalkyne slowly. [32,34] However, such precautions are not invariably necessary and fair yields (20-63%) have been observed in the synthesis of a number of heterocycle-containing ethynylphosphonic esters upon reaction of the corresponding bromoacetylenic alcohols even in benzene at 80°C.…”