2-AZETIDINONE, 4-HYDROXY-ACETATE

Silane, trimethyl[(1-phenylethenyl)oxy]- (13735-81-4), 65, 12 4-ACETOXYAZETIDIN-2-ONE 2-AZETIDINONE, 4-HYDROXY-ACETATE (ESTER) 2-AZETIDINONE, 4-(ACETYLOXY)- (28562-53-0), 65, 135... 

IH-Azepine. hexahydro-2-propyl- (85028-29-1), 66, 193 2H-Azepine, 3,4,5,6-tetrahydro-7-methoxy-, 67,170 2-AZETIDINONE, 4-(ACETYLOXY)-, 65,135 2-AZETIDINONE, 4-HYDROXY-ACETATE (ESTER), 65, 135 2-AZETIDINONE, 3-METHOXY-1.3-DIMETHYL-4-PHENYL-, 65, 140 Azobisisobutyronitrile (AIBN) (78-67-1), 66, 77, 79, 86 67, 86 69, 66 AZOMETHINE YLIDE EQUIVALENT, 67,133... 

Acetoxyazetidin-2-one 2-Azetidinone, 4-hydroxy-acetate (ester) (8) 2-Azetidinone, 4-(acetyloxy)- (9) (28562-53-0)... 

In 2000, the group of Banik et al. reported the enantiospecific synthesis of 3-hydroxy-2-azetidinones by microwave assisted Staudinger reaction [51]. Chiral imines, derived from chiral aldehydes and achiral amines, reacted with methoxy- or acet-oxy-acetyl chloride to afford a single, optically pure c/s-p-lactam, (Scheme 7). 

Appropriately substituted hydroxy amides and ureas can be used instead of diamines. Thus, acid-catalyzed cyclocondensation of iV-carbamoyl prolinols 137 (R1 = H, (CH2)3) (Scheme 27) with aldehydes RCHO (R = Ph, 2-MeOC6H4, 2-naphthyl, etc.) stereoselectively afforded a series of pyrroldine-fused oxadiazepinones 46 (Scheme 5) <1990CPB2627, 1990H(30)287, 1996LA927>. Similar heterocyclization of 4-(2-hydroxyethylthio)-2-azetidinone with acetone dimethyl acetal was used in the synthesis of azetidinone-fused oxathiazepanes of type 33 (X = S) (Figure 4) <1980JA2039>. 

The intramolecular nitrone-alkene cycloaddition reaction of monocyclic 2-azetidinone-tethered alkenyl(alkynyl) aldehydes 211, 214, and 216 with Ar-aIkylhydroxylamincs has been developed as an efficient route to prepare carbacepham derivatives 212, 215, and 217, respectively (Scheme 40). Bridged cycloadducts 212 were further transformed into l-amino-3-hydroxy carbacephams 213 by treatment with Zn in aqueous acetic acid at 75 °C. The aziridine carbaldehyde 217 may arise from thermal sigmatropic rearrangement. However, formation of compound 215 should be explained as the result of a formal reverse-Cope elimination reaction of the intermediate ct-hydroxy-hydroxylamine C1999TL5391, 2000TL1647, 2005EJ01680>. 

Acetic anhydride (10.96 mmol) was added to l-(4-fluorophcnyl-3(//)-(3(.S )-hydroxy-3-(4-fluorophenyl)propyl))-4(5)-(4-hydroxyphenyl)-2-azetidinone (4.98 mmol) containing dimethylaminopyridine (11.96 mmol) dissolved in 15 ml THF and the reaction monitored by TLC using 5% methyl alcohol/toluene. Thereafter, the mixture was then diluted with diethyl ether, washed with 1M HC1 and brine, and dried using Na2S04. The solution was concentrated and the product isolated in 100% yield and used without additional purification. 

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