One-pot Regioselective Synthesis of Nature Mimicking Dihydronaphthofurans and Dibenzofurans

A regioselective approach for the synthesis of substituted naphthofurans and dibenzofurans has been demonstrated through a ring transformation reaction of suitably functionalized 2H-pyran-2-ones by reaction with 6,7-dihydro-5H-benzofuran-4-one and 7-methoxybenzofuran-3-one, respectively in high yields. The novelty of the procedure lies in the creation of an aromatic ring transformed by 2H-pyran-2-one involving the –COCH2- moiety of a cyclic ketone.

Baylis-Hillman reaction assisted synthesis of substituted 5,8-dihydro-isoxazolo[4,5-c]azepin-4-one: A novel isoxazole-annulated heterocycle

The novel synthesis of a new isoxazole-annulated heterocycle namely 5,8-dihydro-isoxazolo[4,5-c]azepin-4-one described herein is based on the reaction of benzyl amine with acetates of Baylis-Hillman adducts generated from 3-aryl-5-formyl-isoxazole-4-carboxylate

Convenient synthesis of substituted α-methylene--valerolactones in aqueous medium using Baylis-Hillman chemistry

A mild and convenient synthesis of substituted α-methylene--valerolactones was achieved by SN2 nucleophilic substitution of the acetates of the Baylis-Hillman adducts with acetyl acetone followed by one-pot saponification of the ester, reduction of the keto group and subsequent intramolecular ring closure in aqueous medium.

Odorless Preparation Of Thioglycosides And Thio Michael Adducts Of Carbohydrate Derivatives

A generalized, odorless, one-pot methodology has been developed for the preparation of 1,2-trans-thioglycosides and thio-Michael addition products of carbohydrate derivatives through triphenyl phosphine mediated cleavage of disulfides and reaction of the thiolate formed in situ with glycosyl bromides and glycosyl conjugated alkenes.

Efficient Synthesis of Glycosyl Enaminoesters Directly from Glycosyl Azides

A convenient methodology has been developed for the synthesis of glycosylenaminoesters directly from glycosyl azides under hydrogenetion condition. Yields were moderate to good in all cases.

Application of primary allyl amines afforded by the Baylis-Hillman adducts for heterocyclic synthesis: Generation of 5-benzyl-4(3H)-pyrimidinones and 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones

The applications of the primary allyl amines afforded by the acetyl derivative of Baylis-Hillman adducts of acrylate for the synthesis of heterocycles using robust reactions are described. In the first strategy a one-pot synthesis of 5-benzyl-4(3H)-pyrimidinones have been achieved via N-formylation of the amines in the presence of neat formamide followed by ammonium formate-mediated cyclization. These pyrimidinones have been demonstrated to be excellent precursor to the 4-pyridinamine derivatives. In the second strategy the synthesis of 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones have been accomplished via treatment of allyl amine with dimethoxyfuran followed by saponification and PPA-mediated intramolecular cyclization.

Synthesis, Optical Resolution, and Configurational Assignment of Novel Axially Chiral Quateraryls

A one-pot, general synthesis of highly functionalized quateraryls through carbanion-induced, base-catalyzed ring transformation of 5,6-diaryl-2H-pyran-2-ones and core-substituted phenylacetones is delineated. These conversions were found to give diversely functionalized benzenes bearing peripheral aryl rings, some of which possess inherent atropisomerism. Exemplarily for one of the quateraryls, the optical resolution of the respective atropo-enantiomers by HPLC on a chiral phase and the assignment of their absolute axial configurations succeeded by LC-CD coupling in combination with semiempirical CNDO/S and TDDFT CD calculations. This synthetic approach offers – in a transition metal-free environment – high flexibility in the construction of quateraryls with the desired conformational freedom along the molecular axis, which may help in exploring and developing new potential ligands for asymmetric synthesis.

Profile and Prevalence of Aspirin Resistance in Indian Patients with Coronary Artery Disease

Background: Aspirin resistance is considered to be an enigma and the data available on aspirin resistance is scarce. This study was initiated to prospectively evaluate the prevalence of aspirin resistance in patients with stable coronary artery disease by using an established method of optical platelet aggregation. Methods and Results: We studied 50 patients who were on 150 mg of aspirin for the previous 7 days. Fasting blood samples were assessed using optical platelet aggregation (Chronolog Corp, USA). The mean platelet aggregation with 10 μm of adenosine diphosphate in our patient group was 49.42 ± 23.29% and with 0.5 mg/ ml of arachidonic acid it was 13.58 ± 21.40%. Aspirin resistance was defined as a mean aggregation of ≥70% with 10 μm of adenosine diphosphate and a mean aggregation of ≥ 20% with 0.5 mg/ml of arachidonic acid. Aspirin semi responders were defined as those meeting only one of the criteria. Based on these criteria, 2.08% patients were found to be aspirin-resistant, 39.58% were aspirin semi responders and 58.33% were aspirin responders. Females tended to be more aspirin semi responsive (p = 0.08). All other parameters tested, namely, age, smoking, diabetes mellitus, hypertension, obesity, lipids, hemoglobin, platelet count, ejection fraction and drug intake did not show any statistically significant difference among the groups. Thus, in our group 41.66% patients showed inadequate response to aspirin. Conclusions: This study shows that aspirin resistance and aspirin semi responsiveness do occur in the Indian patients and there are no reliable clinical predictors for this condition. The diagnosis therefore relies primarily on laboratory tests.