New methods for the preparation of irbesartan 1 have been described. The dehydration and tetrazole formation in one step from substituted cyclopentane derivative 7 with tributyltin chloride and sodium azide is described. Selective hydrolysis of nitrile 3 with HCl has also been described in the preparation of N-acylaminocyclopentane-2-carboxylic acid 4, which is the key intermediate for the preparation of irbesartan. The impurity profiling of irbesartan has also been discussed.

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Synthesis of process related impurities of Nafcillin Sodium 3, generated during the preparation of Nafcillin Sodium Bulk drug is described. The compounds were identified as (

A simple one pot synthetic method for the isomerization of cephem double bond from the natural 3‐position to 2‐cephem positions is affected by silylation. Thus cephalosporin acids are treated with Ntrimethylsilylacetamide (MSA) or N,O‐bis(trimethylsilyl)acetamide (BSA) and the resulting silyl esters are treated with triethylamine at ambient temperature in the same pot to afford Δ2‐cephalosporins, which are potentially related compounds in cephalosporin antibacterial compounds.

Antibiotics U 1200Novel Compounds for the Synthesis of Cefdinir. -Small changes to the new intermediates (III) and (VII) lead to a strong improvement with respect to yields and purity of the antibacterial drug cefdinir (V). This cost-effective and plant-friendly process offers an alternative to currently available methods. Especially intermediate (III) is highly stable and affords high yield of (V) with excellent purity. For the preparation of (III), it is necessary to maintain the water content in (I) < 0.5 %. In the second method, (VI) is dehydrated by azeotropic removal of methylene chloride until the water content is dropped to < 0.05 %. -(RAO, K. V. V. P.; DANDALA*, R.; SIVAKUMARAN, M.; RANI, A.; NAIDU, A.; J. Heterocycl. Chem. 44 (2007) 2, 309-314; Chem. Res. Dep., APL Res. Cent.,