Triethylamine → CEPHALOTHIN ANALOG (3-CH3)

Participants

Reaction Steps

A suspension of the polymer ester of (6R,7R)-7-amino-3-methylceph-3-em-4-carboxylic acid (5.00g, 5.0 m.mole, from example 18) in methylene chloride (100 ml) was stirred at room temperature (18°-21° ) under nitrogen for 30 minutes. After cooling to 0°, triethylamine (3.03g. 0.03 mole) was added, and stirring continued for 30 minutes. Thienylacetyl chloride (3.0 ml, 3.89g, 0.024 mole) was then added dropwise over a period of 10 minutes maintaining the temperature at 0°-5°. When addition was completed stirring was continued for 15 minutes at 0°-5° and for a further 5 hours at room temperature (18°-21° ). The reaction mixture was filtered and pulled as dry as possible. The product was washed with methylene chloride (3 × 100 ml) acetone (2 × 100 ml), water (4 × 100 ml), acetone (2 × 100 ml), and methylene chloride 3 × 100 ml): and dried to constant weight in vacuo at 40° to give a light brown coloured polymer ester of (6R,7R)-3-methyl-7-(2-thienyl) acetamidoceph-3-em-4-carboxylic acid (5.41g). The composition was confirmed by microanalytical data. ν max (Nujol) 3320w (NH), 1780s (β-lactam CO), 1722s (ester CO) abnd 1688s (amide CO) cm-1, τ [CDCl3 and CF3COOH (2:1)] 2.66 (triplet, J = 3.3 Hz: 2-thienyl proton), 2.97 (doublet, J = 3.3 Hz: 3-thienyl protons): 4.27 (double doublet, J 4.5, 9.0 Hz; 7-H), 4.88 (doublet J 4.5 Hz: 6-H), 5.99 (singlet: --CH2CO--), 6.41 and 6.77 (2 doublets, J 18 - 19 Hz: s-CH2), and 7.70 (singlet, --CH3).

Provenance & Evidence