Letters in Organic Chemistry - Volume 12, Issue 6, 2015

The ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS) technique is a new approach in the chromatographic separations and has been successfully employed for fast, high resolution separations with required sensitivity. The TOF-MS is helpful in the structure elucidation and identification of fragmentation patterns of the compounds. This review provides the brief introduction and applications of UHPLC/Q-TOF-MS with examples of some of the most advanced work in the pharmaceutical analysis.

One-pot, four component syntheses for the preparation of 1-H Pyrazolo[1,2-b]phthalazine- 5,10-diones (5a-5h) and 2H-indazolo[2,1-b]phthalazine-1,6,11(13-H)-triones (7a-7f) have been described from phthaloyl dichloride (1) , hydrazine hydrate (2), benzaldehydes (3) and malononitrile (4a), ethyl cynoacetate (4b) or dimedone (6) in refluxing water for 1-1.5 h by in-situ generation of HCl as a catalyst. These reactions have easy workup, provide excellent yields, and use water as the solvent.

A series of ten new 2,3,6-substituted quinazolin-4(3H)-one derivatives (10a-j) were prepared from anthranilic acid (1) in a simple and economical path in a series of reactions and screened for their anticancer activity against pancreatic cancer cell line (PANC-1) using MTT assay. The results reveal that at concentration 100 μM/L, compounds 10b, 10f, 10g and 10h exhibited potential anticancer activity by inhibiting the growth of PANC-1 cells by >75% and remaining compounds showed moderate anticancer activity. The structural characterization of the synthesized compounds was elucidated by 1H & 13C NMR, LC-MS, FT-IR and elemental analysis. As potential anti-tumor agents, these new derivatives show promise for further research.

In this study, is reported a straightforward route is reported for the synthesis of a series of carbamazepine derivatives using some strategies. The first stage was achieved by the reaction of carbamazepine with thiourea in the presence of pyridine to form the compound 3-(5H-dibenzo[b,f]azepin-5-yl)-2,5-dihydro-1,2,4-thiadiazol-5-amine (3). After 3 was made reacting with chloroacetyl chloride using triethylamine as catalyst to synthesis of a propanamide derivative (4). The following stage a carboxamide derivative (5) was synthesized by the reaction of 4 with benzaldehyde in basic medium. The fourth stage was achieved by the reaction of carbamazepine with ethylenediamine in presence of formaldehyde to form a new carboxamide derivative (7). Then, the compound 7 was made reacting with 2-hydroxy-1-naphthaldehyde using boric acid as catalyst to synthesis of a carbamazepine derivative (8). Finally, 8 was made reacting with 3,5- dintrobenzoic acid in the presence of dimetyhyl sulfoxide at mild conditions to form a new carbamazepine derivative 9. The structure of the compounds obtained was confirmed by elemental analysis, spectroscopy and spectrometry data. The proposed method offers some advantages such as simple procedure, low cost, and ease of workup.

The new index for the evaluation of the aromatic character based on the energy of π orbitals.

A series of ten new 2,3,6-substituted quinazolin-4(3H)-one derivatives (10a-j) were prepared from anthranilic acid (1) in a simple and economical path in a series of reactions and screened for their anticancer activity against pancreatic cancer cell line (PANC-1) using MTT assay. The results reveal that at concentration 100 µM/L, compounds 10b, 10f, 10g and 10h exhibited potential anticancer activity by inhibiting the growth of PANC-1 cells by >75% and remaining compounds showed moderate anticancer activity. The structural characterization of the synthesized compounds was elucidated by 1H & 13C NMR, LC-MS, FT-IR and elemental analysis. As potential anti-tumor agents, these new derivatives show promise for further research.

Synthesis of the trisaccharide, benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-Dglucopyranosyl-(1→3)-2,4,6-tri-O-benzyl-β-D-galactopyranosyl-(1→4)-2,3,6-tri-O-benzyl-β-Dglucopyranoside (9), was achieved from building block derivatives of the component mono- and disaccharide units. Initially the benzyl lactoside acceptor 3, which has a free hydroxyl group at position O-3`, was prepared via selective opening of the 3',4'-cyclic orthoester derivative 2. The glucosaminyl donor, 2-methyl (3,4,6-tri-O-acetyl-l,2-dideoxy-(α-D-glucopyrano)-[2`,1`:4,5]-2-oxazoline (4), was coupled to 3 affording the trisaccharide glycoside 5 in a good yield. Successive de-O-acetylation (5→6), benzylidenation (6→7), benzylation (7→8) and reductive opening of the benzylidene acetal function of 8 gave the target trisaccharide 9, which is a useful building block for the construction of complex oligosaccharides.

An efficient eco-friendly approach has been adopted for the selective synthesis of 2,3- epoxypropylsulfanyltriazole 4 from the reaction of 1-chloro-2,3-epoxy-propane (2) with 5-(3- chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole-3-thione (1) under solvent free microwave conditions in the presence of a solid support. Instead, when the mixture of reactants was irradiated for prolonged time in the absence of solid support, triazolo[ 2,1-b]thiazine 3 was exclusively afforded in excellent yield. On the other hand, performing the irradiation in the presence of a base, mixtures of compounds 4 and 3 were obtained; the ratio of the two products was dependent on the nature of the base, although 4 was the major product in each case.

A concise stereoselective total synthesis of (-) - Cephalosporolide D, an eight membered lactone ring has been derived from low cost and easily available starting material (±)-propylene epoxide. The key steps involved in this concise synthesis are Sharpless kinetic resolution, Grignard reaction and Yamaguchi macrolactonisation.