Orthoester


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Orthoester

 

RC(OR′)3, an ester of carboxylic orthoacids, RC(OH)3, where R is an organic radical or hydrogen. In contrast to orthoacids, orthoesters are stable compounds. The simplest occur as colorless liquids with an ethereal odor and are nearly insoluble in water but readily soluble in organic solvents. Orthoesters readily hydrolyze in a weak acid medium but remain stable in alkaline media. One method of obtaining orthoesters is to react 1,1,1-trihalide hydrocarbons with alcoholates of alkali metals, for example, HCCl3 + 3NaOC2H5 → HC(OC2H5)3 + 3NaCI. Orthoesters are useful in organic chemistry, for example, orthoformic acid esters are used in the synthesis of acetals, aldehydes, and ketones.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
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 [36] and acetylenic groups [37-38], [beta]-ketosters [39-40], [alpha]-haloacids [41] and malonates [42].
(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 [16] (Scheme 2).