179057-31-9

Two sets of reaction conditions for the regiodivergent C2- or C5- direct arylations of oxazole are reported. In both cases, phosphine-free catalysts and inexpensive bases were employed allowing the access to the arylated oxazoles in moderate to high yields. Using Pd(OAc)2/KOAc as catalyst and base, regioselective C5-arylations were observed; whereas, using Pd(acac)2/Cs2CO3 system, the arylation occurred at the C2-position of oxazole. The higher reactivity of C5-H bond of oxazole as compared to the C2-H bond in the presence of Pd(OAc)2/KOAc system is consistent with a concerted metalation deprotonation mechanism; whereas the C2-arylation likely occurs via a simple base deprotonation of the oxazole C2-position. Then, from these C2- or C5-arylated oxazoles, a second palladium-catalyzed direct C?H bond arylation affords 2,5-diaryloxazoles with two different aryl groups. We also applied these sequential arylations to the straightforward synthesis of 2-arylphenanthro[9,10-d]oxazoles via three C?H bond functionalization steps. The Ru-catalyzed C?H arylation of the aryl unit of 2-aryloxazoles is also described. (Figure presented.).

A facile synthetic route to the new 2-TIPS-oxazol-5-ylboronic acid pinacol ester was described herein. Its reactivity toward Suzuki cross-coupling reaction was studied to provide various 5-(het)aryloxazoles. A wide range of functions on the aryl moiety ar

To provide a diagnostic drug which binds specifically to an amyloid aggregate and/or an amyloid deposit, to thereby realize imaging and quantification of a disease caused by amyloid aggregation and/or deposition. The invention provides a compound represented by formula (1) : (wherein X1 represents an optionally substituted bicyclic heterocyclic group; X2 represents a hydrogen atom, a halogen atom, or a chelate-forming group; ring A represents a benzene ring or a pyridine ring; and ring B represents an optionally substituted 5-membered aromatic heterocyclic group which is bonded to the benzene ring or the pyridine ring via a carbon atom of ring B), a salt thereof, a solvate of any of these, or a transition metal coordination compound of any of these, and a diagnostic, preventive, or therapeutic drug containing the same.

A series of N-alkyl-N-(heteroaryl-substituted benzyl)-N'-arylurea and related derivatives represented by 2 and 3 have been prepared and evaluated for their ability to inhibit acyl-CoA:cholesterol O-acyltransferase in vitro and to lower plasma cholesterol levels in cholesterol-fed rats in vivo. Among these novel compounds, the type 3 series was superior. A pyrazol-3-yl group on the N-benzyl group of this trisubstituted urea (i.e. 3, Ar1 = pyrazol-3- yl) was identified as a heteroaromatic ring providing a good profile of biological activity. As a result of optimization of the combination with the N-alkyl group (R) and N-aryl group (At3), compound 3aq (FR186054) was identified as a new, orally efficacious ACAT inhibitor, which exhibited potent in vitro ACAT inhibitory activity (rabbit intestinal microsomes IC50 = 99 nM) and excellent hypocholesterolemic effects in cholesterol-fed rats, irrespective of administration mode (ED50 = 0.046 mg/kg dosed via the diet, ED50 = 0.44 mg/kg administered by gavage in PEG400 vehicle). Moreover, a toxicological study revealed compound 3aq to be nontoxic to the adrenal glands of dogs when tested at a single dose of 10 mg/kg po.