Furo pyrimidine-2,4-diones

The use of a pyrimidine precursor continues to be the more popular approach to furo pyrimidines. The one-pot three-component condensation reactions of alkyl or aryl isocyanides with A[A -dimethylbarbituric acid in the presence of terephthaldialdehyde proceeded spontaneously at room temperature in DMF to give good yields of the corresponding l,4-bis(6-alkyl or arylamino-1,3-dimethylfurano[2,3-4]pyrimidin-2,4(l//,3//)-dione-5-yl)benzenes <2006BMCL3697>. 

Furo[2,3-amino-synthesis, 4, 986 Furo[3,4-d]pyrimidinedione synthesis, 4, 987 Furopyrimidines, 4, 986 Furo[2,3-d]pyrimidines synthesis, 4, 986 Furo[3,2-d]pyrimidines synthesis, 4, 987 Furo[3,2- 6]pyrone synthesis, 4, 994 Furo[3,2-c]pyrone synthesis, 4, 993 Furo[3,2-6]pyrrole, hexahydro-biological activity, 6, 1024 1 H-Furo[3,4-6]pyrrole-2,3-dione, 4,6a-diphenyl-6-(phenylimino)-6,6a-dihydro-synthesis, 6, 1004 Furopyrroles... 

Finally, a one-pot, three-component condensation reaction in water provides an efficient procedure for the synthesis of furo[2,3-r/ pyrimidine-2,4(1/7,3//)-diones 303 (Scheme 26). A, A -Dimethylbarbituric acid 301 and 4-nitrobenzaldehyde 302 are reacted with a series of isocyanides to give good yields of the 6-amino products 303 <2002TL9151, 2005SC535>. 

Shaabani and co-workers reported the synthesis of furo[2,3-d]pyrimidine-2,4 (lH,3H)-diones via the three-component condensation of -dimethylbarbituric acid, aldehyde, and an alkyl or aryl isocyanide in l-butyl-3-methylimidazolium bromide ([bmim][Br]) as the solvent and promoter at room temperature (Fig. 12.17) [13]. 

Shaabani A, Soleimani E, Darvishi M (2(X)7) Ionic liquid promoted one-pot synthesis of furo[2,3-d]pyrimidine-2,4(l 77,3/f)-diones. Monatsh fiir Chemie 138 43-46... 

V3-Substituted furo[3,4-(/]pyrimidine-2,4-diones (642) with a number of dienophiles give Diels-Alder adducts under unusually mild reaction conditions (Scheme 103). The regioisomeric 5,8-epoxy-... 

A comprehensive study has investigated multidirectional cyclative cleavage transformations leading to bicyclic dihydropyrimidinones [61]. This approach required synthesis of 4-chloroacetoacetate resin as the key starting material this was prepared by microwave-assisted acetoacetylation of commercial available hydroxymethyl polystyrene resin under open-vessel conditions. This resin precursor was subsequently treated with urea and a variety of aldehydes in a Biginelli-type multi-component reaction, leading to the corresponding resin-bound dihydropyrimidinones (Scheme 16.40). The desired furo[3,4-d]pyrimidine-2,5-dione scaffold was obtained by a novel procedure for cyclative release under the action of micro-wave irradiation in sealed vials at 150 °C for 10 min. 

The S5mthesis of furopyrimidines has received a little attention in spite of their wide range of associated bioactivities including antimicrobial, antiviral, antimicotic, and antiplatelet [84-86]. Shaabani et al. reported a three-component condensation reaction of N,N -dimethylbarbituric acid with aldehydes and alkyl or aryl isocyanides at room temperature (RT) in the presence of [BMIM][Br] in a molar ratio of 1 1 (reactant/IL) to afford furo[2,3-d]pyrimidine-2,4(lH,3H)-diones 32 (Scheme 6). The authors cited that the presence of an electron-withdrawing group was necessary and addition of [BMIM][Br] was crucial for the formation of the desired product in high yield [87]. 

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