Reactions of 2-amino-2-thiazolines with isocyanates and isothiocyanates. Chemical and computational studies on the regioselectivity, adduct rearrangement, and mechanistic pathways

New heat resistant poly (thiourea-amide-imide)s derived from 1-(1,3-dioxo-2-(4-aminophenyl) isoindolin-5-yl)carbonyl-3-(4-aminophenyl) thiourea for high performance applications

Novel heat-resistant and organosoluble poly(thiourea-amide-imide)s (PTAIs) were synthesized through the condensation of trimellitic anhydride chloride (TMAC)-derived imide ring bearing diamine (1-(1,3-dioxo-2-(4-aminophenyl)isoindolin-5-yl)carbonyl-3-(4-aminophenyl) thiourea) with various diacid chlorides. Physical properties of PTAIs including crystallinity, organosolubility, thermal properties, flame retardancy, solution viscosity along with molecular weights were investigated. Accordingly, polymers bearing phenylthiourea moieties displayed an amorphous nature and were readily soluble in amide solvents having ηinh of 1.11–1.37 dL g−1. Moreover, gel permeation chromatography measurements revealed Mw around 76 869–80 391. Thermal stability of these polymers was ascertained via 10% weight loss temperatures around 517–544°C in an inert atmosphere. Furthermore, glass transition temperatures of PTAIs were found to be 286–292°C. Limiting oxygen index (LOI) measurements indicated that new copolymers were efficiently flame retardant as compared to several reported materials. Hence, incorporation of thiourea functionalities into the polymer backbone was demonstrated to be an effective way to enhance their thermal properties and flame retardancy.

Synthesis and thermal behavior of novel poly(thiourea-amide)s derived from 1-(4-aminobenzoyl)-3- (3-aminophenyl) thiourea

The novel difunctional monomer, 1-(4-aminobenzoyl)-3-(3-aminophenyl) thiourea (ABAPT), was synthesized by the reduction of NBNPT (1-(4-nitrobenzoyl)-3-(3-nitrophenyl) thiourea). The characterization of the monomers was carried out using spectroscopic and elemental analyses. A series of novel aromatic and aromatic-aliphatic poly (thiourea-amide)s (PAMDs) were obtained through the condensation of ABAPT with various diacid chlorides (terephthaloyl, isophthaloyl, sebacoyl and adipoyl chloride). Structural elucidation of the resulting polyamides was carried out by FTIR, 1H- and 13C-NMR techniques along with solvent miscibility, viscosity, molecular weight, crystallinity, non-flammable and thermal studies. The polymers bearing phenylthiourea moieties in the backbone were obtained in quantitative yield. PAMDs having inherent viscosities of 1.02-1.32 dL g−1 exhibited good organosolubility in amide solvents ( N, N-dimethylacetamide, dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone). X-ray diffraction studies specified crystalline behavior of new polyamides. Gel permeation chromatography measurements disclosed Mw around 34 000-65 000. The thermogravimetric analyses and limiting oxygen index measurements indicated that aromatic polyamides were stable up to 500 °C and were adequately flame retardant. Moreover, their glass transition temperatures were found to be 265-273 °C.

Intra- and inter-molecular phosphoryl migration in phosphinothiazolines; precursors to polynuclear complexes and bimetallic coordination polymers

Two tautomers of the new phosphinoaminothiazoline Ph2PNHC=NCH2CH2S, obtained from the reaction of 2-amino-2-thiazoline (ATHZ) with Ph(2)PCl, have been structurally characterized and the intermediate formation of the diphosphine Ph2PN=CN(PPh2)CH2CH2S has been demonstrated experimentally and by DFT calculations; reacts with [AuCl(THT)] to give [(AuCl)2] whereas the bidentate metalloligand cis-[Pt(1(-H))2] reacts with AgOTf to form the Ag-Pt coordination polymer [Ag(infinity)[Pt(1(-H))2](infinity)](OTf)(infinity).

Synthesis and anti-histaminic evaluation of N-phenyl-(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines

New N-phenyl(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines, 5a-e, have been synthesized from the corresponding 3-phenyl(alkyl)carbamoyl-2-iminooxazolidines 2. A two-stage hydrolysis reaction led finally to the corresponding ring-opened N-phenyl(alkyl)-N'-[1-(3-(dialkylamino)-propan-2-ol)]ureas 4. The oxazoline ring was regenerated through an intramolecular nucleophilic substitution involving an halogen atom introduced by the reaction of thionyl chloride on 4. Pharmacological properties of 5a-e were evaluated on histaminic and adrenergic receptors in guinea-pig trachea and rat aorta. Compounds 5b and 5e showed a selective anti-histaminic effect on guinea-pig airways, but a significant response was obtained for a concentration >10(-6) M. No pharmacological activity was obtained with oxazoline 5c whereas oxazolines 5a and 5d seemed to present a non-selective effect on the contractile mechanism of the smooth muscle cell.

Derivatization of (+/-)-5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate for drug monitoring purposes

The derivatization of racemic 5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, developed as an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate was performed in chloroform. The reaction led to two pairs of diastereomers, which were separated by RP-HPLC. A kinetic study of the derivatization reaction was achieved in order to establish conditions suitable for experimental drug monitoring.