Abstract: This invention features pyrimidine compounds of formula (I): R1 is aryl, or heteroaryl; each of R2 and R4, independently, is Rc, halogen, nitro, cyano, isothionitro, SRc, or ORc; or R2 and R4, taken together, is carbonyl; R3 is Rc, alkenyl, alkynyl, ORc, OC(O)Rc, SO2Rc, S(O)Rc, S(O2)NRcRd, SRc, NRcRd, NRcCORd, NRcC(O)ORd, NRcC(O)NRcRd, NRcSO2Rd, CORc, C(O)ORc, or C(O)NRcRd; R5 is H or alkyl; n is 0, 1, 2, 3, 4, 5, or 6; X is O, S, S(O), S(O2), or NRc; Y is a covalent bond, CH2, C(O), C?N—Rc, C?N—ORc, C?N—SRc, O, S, S(O), S(O2), or NRc; Z is N or CH; one of U and V is N, and the other is CRc; and W is O, S, S(O), S(O2), NRc, or NC(O)Rc; in which each of Ra and Rb, independently, is H, alkyl, aryl, heteroaryl; and each of Rc and Rd, independently, is H, alkyl, aryl, heteroaryl, cyclyl, heterocyclyl, or alkylcarbonyl.

Abstract: This invention features pyrimidine compounds of formula (I): R1 is aryl, or heteroaryl; each of R2 and R4, independently, is Rc, halogen, nitro, cyano, isothionitro, SRc, or ORc; or R2 and R4, taken together, is carbonyl; R3 is Rc, alkenyl, alkynyl, ORc, OC(O)Rc, SO2Rc, S(O)Rc, S(O2)NRcRd, SRc, NRcRd, NRcCORd, NRcC(O)ORd, NRcC(O)NRcRd; NRcSO2Rd, CORc, C(O)ORc, or C(O)NRcRd, R5 is H or alkyl; n is 0, 1, 2, 3, 4, 5, or 6; X is O, S, S(O), S(O2), or NRc; Y is a covalent bond, CH2, C(O), C?N—Rc, C?N—ORc, C?N—SRc, O, S, S(O), S(O2), or NRc; Z is N or CH; one of U and V is N, and the other is CRc; and W is O, S, S(O), S(O2), NRc, or NC(O)Rc; in which each of Ra and Rb, independently, is H, alkyl, aryl, heteroaryl; and each of Rc and Rd, independently, is H, alkyl, aryl, heteroaryl, cyclyl, heterocyclyl, or alkylcarbonyl.

Abstract: This invention features pyrimidine compounds of formula (I): 1

Abstract: This invention features pyrimidine compounds of formula (I): aryl, or heteroaryl; each of R2 and R4, independently, is Rc, halogen, nitro, cyano, isothionitro, SRc, or ORc; or R2 and R4, taken together, is carbonyl; R3 is Rc, alkenyl, alkynyl, ORc, OC(O)Rc, SO2Rc, S(O)Rc, S(O2)NRcRd, SRc, NRcRd, NRcCORd, NRcC(O)ORd, NRcC(O)NRcRd, NRcSO2Rd, CORc, C(O)ORc, or C(O)NRcRd; R5 is H or alkyl; n is 0, 1, 2, 3, 4, 5, or 6; X is O, S, S(O), S(O2), or NRc; Y is a covalent bond, CH2, C(O), C═N—Rc, C═N—ORc, C═N—SRc, O, S, S(O), S(O2), or NRc; Z is N or CH; one of U and V is N, and the other is CRc; and W is O, S, S(O), S(O2), NRc, or NC(O)Rc; in which each of Ra and Rb, independently, is H, alkyl, aryl, heteroaryl; and each of Rc and Rd, independently, is H, alkyl, aryl, heteroaryl, cyclyl, heterocyclyl, or alkylcarbonyl.

Abstract: The proportioning valve assembly (40, 140) may be screwed into a complementary-shaped opening in a master cylinder (10). The valve assembly (40, 140) includes a differential area piston (50, 150) biased by a spring (70, 170) toward the outlet (21, 121) which communicates with the rear brakes. The master cylinder (10) includes a pair of passageways (16, 18) which communicate primary fluid pressure and secondary fluid pressure directly to the differential area piston (50, 150) of the proportioning valve assembly (40, 140) to displace the piston (50, 150) to a balanced position. If there is a failure of pressure in the primary brake circuit, the proportioning valve assembly (40, 140) actuates the differential area piston (50, 150) to permit fluid flow to bypass the piston (50, 150) and be communicated directly to the rear brakes of the vehicle.