Reaction of aryl chloroformates with dimethylformamide. Facile in situ synthesis of .alpha.-chlorocresols

Model studies on the mechanism of biotin-dependent carboxylations. 2. Site of protonation vs. carbon dioxide transfer

“…Poropak R column; temperature program, 70-250 °C at 4 °C/min; flow rate, 40 cm3/min. The retention time for dimethyl ether was 2.8 min; MS m/e (rel %) 46 (53), 45 (100), 29 (71). The retention time for methyl ethyl ether was 5.6 min; MS m/e (rel %) 60 (33), 59 (12), 45 (100), 43 (6), 31 (14), 29 (31), 28 (6), 27 (12), 15 (9); NMR (CDCI3) 1.19 (t, J = 7.0 Hz, 3 H), 3.35 (s, 3 H), 3.46 (q, J = 7.0 Hz, 2 H).…”

Self‐aggregation behavior of amphiphilic polyaspartamide derivatives containing cholesterol moieties

“…The number of cholesterol molecules per copolymer chain (CPC) was calculated on the basis of number of repeat polyaspartamide (PolyAspAm) units. The conjugation reaction gave a low yield due to (1) a difference in the hydrophilic and hydrophobic properties between the copolymer chain and the Chol pendant and (2) the high reactivity of the chloroformate group with moisture, even in the DMF solvent 17. In the case of the PNIEA–Chol system with NIPEDA groups, the efficiency of the reaction increased, probably because of the catalytic effect of neighboring secondary amine groups.…”

Combination anti-HIV therapy via tandem release of prodrugs from macromolecular carriers

“…The restrictive solubility of 3TC in polar aprotic solvents such as DMF or DMSO also rendered nitrophenyl carbonate activation inaccessible via reaction with aryl chloroformates, such as 4-nitrophenyl chloroformate, since these are known to react with DMF. 38 As such, synthesis of 4 was performed with the bis(4-nitrophenyl) carbonate in lieu of the 4-nitrophenyl chloroformate. This posed an additional issue where the 4-nitrophenol compound smeared over the silica column causing contamination of the fractions collected.…”