A New Synthesis of α-Bromoaldehydes

Abstract

The dimer (100 mg.) was dissolved in acetic acid (8 cc.) containing hydrobromic acid (8 cc., 48%), and the solution was boiled for twenty minutes. The mixture rapidly became dark and no pure product could be isolated from it.Dithymoquinone (100 mg.) in ether (30 cc.) was shaken with a solution of sodium hydrosulfite (2 g.) in water (20 cc.) until the color was discharged (forty minutes). From

New substrates of acetylcholinesterase

“…The kca t values were ),104 rain -1 (table 1), much slower than that of aromatic esters [5,6], but ~2 orders of magnitude faster than the amide analogue of acetylcholine (kca t = 2.2 X 102 min -l) [8]. EOH + H ÷ + CH3COO- (3) in which EOH is the AChE serine enzyme, EOCOCH 3 is the transient acetyl enzyme, k2 is acylation rate and k3 is deacylation rate constant.…”

“…Phenothlazine-10-carbonyl chloride (PTCC, (a) in fig.l) o-nitro chloroacetanilide VII n-butanal and acetic anhydride [3], and tropolone acetate (VI, fig.l) from tropolone and acetic anhydride [4]. Hydrolysis rates of esters were followed pH-statically.…”

“…Other acetates were prepared according to reported procedures. For example, 1-butenylacetate was prepared from o-nitro chloroacetanilide VII n-butanal and acetic anhydride [3], and tropolone acetate (VI, fig.l) from tropolone and acetic anhydride [4]. Hydrolysis rates of esters were followed pH-statically.…”

Preparation and Reactions of Aliphatic 2‐Pentafluorosulfanyl Aldehydes

“…We found that with Et 3 B initiation, SF 5 Br adds easily to enol acetates, prepared by using either isopropenyl acetate with p ‐toluensulfonic acid11 or a mixture of potassium acetate and acetic anhydride,12 to form bromo‐SF 5 ‐acetates 8 as a 3:1 mixture of diastereomers (Scheme ).…”

“…Dimethyl acetals 10 resulting from heating under reflux with methanol can easily be hydrolyzed to 9 (Scheme ) 13. Alternatively, direct hydrolysis of 8 by using a mixture of hydrochloric acid and glacial acetic acid is efficient 12. Attempts to use milder conditions with lithium halide or metal oxide salts were not effective 14.…”