87153-27-3

Upstream product

• 4457-32-3 4-nitrobenzyl chloroformate 
• 87153-36-4 4-nitrobenzyl 4-<3(R)-benzoylamino-2-azetidinon-4(R)-yloxy>-acetoacetate 
• 95967-24-1 4-nitrobenzyl 4-<3(R)-benzoylamino-2-azetidinon-4(R)-yloxy>-2-butynoate 
• 95967-48-9 4-nitrobenzyl 4-hydroxy-2-butynoate 
• 87153-26-2 4-nitrobenzyl 4-<3(R)-benzoylamino-2-azetidinon-4(R)-yloxy>-2-diazo-3-oxo-butanoate 

Downstream Products

• 87153-28-4 4-nitrobenzyl (6R,7R)-7-benzoylamino-3-methoxy-8-oxo-5-oxa-1-azabicyclo<4.2.0>oct-2-ene-2-carboxylate 
• 95967-32-1 4-nitrobenzyl (6R,7R)-7-benzoylamino-3-chloro-8-oxo-5-oxa-1-azabicyclo<4.2.0>oct-2-ene-2-carboxylate 

Relevant academic research and scientific papers

Process for the preparation of 7-acylamino-3-hydroxy-cephem-4-carboxylic acids and 7-acylamino-3-hydroxy-1-dethia-1-oxacephem-4-carboxylic acids

A process for the preparation of a 7-acylamino-3-hydroxy-2-cephem-4-carboxylic acid, 7-acylamino-3-hydroxy-1-dethia-1-oxa-3-cephem-4-carboxylic acid or derivative thereof of the general formula STR1 in which R1 is hydrogen or optionally substituted alkyl, alkenyl, alkinyl, aralkyl, aryl, heteroaryl, heteroaralkyl, aryloxyalkyl, heteroaryloxyalkyl, alkoxyalkyl, arylthioalkyl, heteroarylthioalkyl, alkylthioalkyl, alkoxy, aryloxy, alkylthio or arylthio, R2 is hydrogen, a carboxy-protective group or a pharmaceutically useful ester radical, and X is sulphur or oxygen, which comprises: (a) reacting a compound of the formula STR2 with (i) a compound of the formula STR3 in which R2 and X have the abovementioned meaning and Y represents diazo (N2) or hydrogen (H2) in an inert solvent in the presence of a Lewis acid or proton acid catalyst, or (ii) a compound of the formula to form an intemediate compound having a triple bond, and hydrating the triple bond, the compounds thus obtained, for Y being hydrogen (H2)--(in case of Y=diazo (N2) directly the compounds of general formula (2) are obtained) thereby to produce a compound of the formula STR4 (b) reacting such compound with an azide in a solvent in the presence of a base to give a compound of the formula STR5 (c) converting said compound to the desired product by (i) irradiation in an inert solvent, or (ii) warming in the presence of a catalyst. The end products are, or can be converted to, known β-lactam antibiotics.

A CONVERGENT SCHEME FOR THE STEREOSELECTIVE SYNTHESIS OF 3'-NOR-1-OXACEPHEMS

A convergent approach to the construction of the 3-hydroxy-oxacephems 1, valuable intermediates for the synthesis of 3'-nor-1-oxacephems, is presented.The key step utilizes the Lewis acid catalyzed stereoselective ring-opening of the oxazoline 2 by an app