Keywords: Quinazolin-4(3H)-one, Microwave, SbCl3, Solvent-free, Orthoester.
Anthranilic acid (4) (10 mmol), orthoester (2) (12 mmol), ammonium acetate (14mmol) and catalytic amounts of SbCl3 were mixed thoroughly in a microwave reactor, equipped with a condenser.
Summary: Efficient and fast condensation of anthranilic amide or anthranilic acid with various orthoesters have been carried out using a catalytic amount of Antimony(III) chloride (SbCl3) under microwave irradiation to afford a series of 2-substituted quinazolin-4(3H)-ones in good to excellent yields under solvent free condition.
DDs are believed to be derived from a tigliane precursor and have an orthoester motif, though a very large number of DDs were identified, they occurred only in the plant families of Thymelaeaceae and Euphorbiaceae (Evans and Soper, 1978).
The potent irritancy of the daphnane orthoester, resini feratoxin, exhibits features of a mixed aetiology.
Furthermore, the biodegradability of these polymers can be easily manipulated by incorporating a variety of labile groups such as ester, orthoester
, anhydride, carbonate, amide, urea, and urethane in their backbone.
These types of fused benzothiazole-pyrimidine compounds have been synthesized from 2-amino-benzothiazoles derivatives and [beta]-haloesters [29-31], orthoesters
[32-35], allenic  and acetylenic groups [37-38], [beta]-ketosters [39-40], [alpha]-haloacids  and malonates .
(31) Leadley, S.R., Shakesheff, K.M., Davies, M.C., Heller, J., Franson, N.M., Paul, A.J., Brown, A.M., and Watts, J.M., "The Use of SIMS, XPS, and In Situ AFM to Probe the Acid Catalysed Hydrolysis of Poly(orthoesters
)," Biomaterials, 19, 1353 (1998).
The Patent Office rejected the compositions claims as obvious, reasoning that the combination of tetra-orthoesters and hydrocarbon fuel was suggested, albeit for a different purpose, by the known tri-orthoester fuel combinations and the structural similarity of the two types of orthoesters
. (141) The Federal Circuit, en banc, affirmed the rejection, holding that the use of a structurally similar molecule in prior art compositions, even for a different purpose, rendered the composition claims prima facie obvious.
Chemical properties related to the carboxyl group: Introduction; Hydrolysis; Esterification; Acid chlorides, acid anhydrides and ketene dimers; Peroxy acids and esters; Long-chain alcohols; Acetals/ketlas and orthoesters
; Nitrogen-containing compounds; Sulfonation and other reactions at the a-position; Barton reaction.
In a previous communication, hetero- cyclization of 7-hydrazinyl-5-methyl-1-phenyl-3- phenyldiazenyl-1H-pyrimido [4,5-e] [1,3,4] thiadiazine 2f with orthoesters
was studied by NOE technique and it showed that 1H-[1,2,4] triazolo[4',3':1,2]pyrimido[4,5-e][1,3,4]thiadiazines have been formed as sole product  (Scheme 2).