- 1,1-Diacyloxy-1-phenylmethanes as versatile N-acylating agents for amines
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1,1-Diacyloxy-1-phenylmethanes and 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as bench stable N-acylating reagents for primary and secondary amines and anilines under solvent-free conditions to afford their corresponding amides in good yield.
- Chapman, Robert. S.L.,Tibbetts, Joshua. D.,Bull, Steven. D.
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p. 5330 - 5339
(2018/06/15)
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- Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
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Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
- Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
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p. 6442 - 6452
(2018/10/02)
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- A facile and efficient conversion of aldehydes into 1,1-diacetates (acylals) using iron(III) fluoride as a novel catalyst
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Aldehydes are smoothly converted into the corresponding 1,1-diacetates (acylals) in high yields in the presence of a catalytic amount (0.1 mol-%) of iron(III) fluoride at room temperature. The noteworthy features of the present system are shorter reaction times, chemoselective protection of aldehydes, and solvent-free conditions. The procedure is especially useful for large-scale syntheses as the catalyst is highly effective from the view of activity, selectivity, reusability, and economy in the preparation of 1,1-diacetates (acylals). CSIRO 2007.
- Kamble,Tayade,Davane,Kadam
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p. 590 - 594
(2008/03/11)
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- Preparation of geminal diacylates (acylals) of aldehydes - Scope and reactivity of aldehydes with acid anhydrides
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The geminal diacylates of a variety of aldehydes were prepared in good yields without any catalysts or solvent by simply refluxing the aldehydes with aliphatic acid anhydrides. The scope of the reactions and relative reactivities of aldehydes and acid anhydrides were examined. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Rahman, Motiur A. F. M.,Jahng, Yurngdong
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p. 379 - 383
(2007/10/03)
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- A stable intermediate: a new insight into the mechanism of Lewis acids-promoted formation of acylals from aldehydes
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Treatment of m-nitrobenzaldehyde with acetic anhydride in the presence of Lewis acids, such as InBr3, ZnBr2, Cu(OTf)2, gives a stable intermediate at the initial stage of reaction. Based on this new organic compound characterized by X-ray single crystal diffraction, a new mechanism for Lewis acids-promoted formation of acylals from aldehydes is proposed. Exchange reaction with different ratio of acetic anhydride to propionic anhydride, in the presence of Lewis acids, is studied.
- Yin, Liang,Zhang, Zhan-Hui,Wang, Yong-Mei
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p. 3119 - 3122
(2008/02/02)
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- Ytterbium perfluorooctanesulfonate catalyzed synthesis of acylals from aldehydes and acetic anhydride in a fluorous biphasic system
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Ytterbium perfluorooctanesulfonate [Yb(OPf)3] catalyses the highly efficient synthesis of acylals from aldehydes and acetic anhydride in a fluorous biphase system (FBS) composed of toluene and perfluorodecalin. The fluorous phase containing the fluorous catalyst is easily separated and can be reused several times without significant loss of catalytic activity.
- Yi, Wen-Bin,Yin, Ya-Qing,Cai, Chun
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p. 1563 - 1566
(2007/10/03)
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- Reinvestigation of the mechanism of gem-diacylation: Chemoselective conversion of aldehydes to various gem-diacylates and their cleavage under acidic and basic conditions
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The mechanism of gem-diacylate formation has been studied extensively using tetrabutylammonium tribromide (TBATB) as the catalyst. The reaction proceeds by a nucleophilic attack of an anhydride on an aldehydic carbonyl group, nucleophilic attack of the hemiacylate intermediate on a second molecule of the anhydride, followed by an intermolecular attack of a second acetate group to regenerate the anhydride. gem-Diacylates of various aliphatic and aromatic aldehydes were obtained directly from the reaction of a variety of aliphatic and aromatic acid anhydrides in the presence of a catalytic quantity of tetrabutylammonium tribromide (TBATB) under solvent-free conditions. A significant electronic effect was observed during its formation as well as deprotection to the corresponding aldehyde. Chemoselective gem-diacylation of the aromatic aldehyde containing an electron-donating group has been achieved in the presence of an aldehyde containing an electron-withdrawing group. Deprotection of the gem-diacylate to the parent carbonyl compound can be accomplished in methanol in presence of the same catalyst. Here again, chemoselective deprotection of the gem-diacylate of a substrate containing an electron-donating group has been achieved in the presence of a substrate containing an electron-withdrawing group. Both the acid and base stability order of the various gem-diacylates examined follow a similar order. The stability order determined from the present study is: gem-dibenzoate > gem-dipivalate > gem-diisobutyrate > gem-diacetate > gem-dipropionate. All the gem-diacylals are more stable under basic conditions than acidic condition. No correlation was found between the stability order and the pKa's of the corresponding acids; rather, the stability order is directly related to the steric crowding around the carbonyl carbon. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Kavala, Veerababurao,Patel, Bhisma K.
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p. 441 - 451
(2007/10/03)
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- Reductive esterification of aromatic aldehydes using Zn/Ac 2O/imidazole or Zn/Yb(OTf)3/(RCO)2O system
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Benzaldehydes are reduced by metallic zinc in the presence of Ac 2O and imidazole, giving the corresponding benzyl acetates in good yields. Reductive esterification of aromatic aldehydes is also carried out via gem-diacetoxy compounds. Carbonyl compounds are readily converted to the gem-diacyloxy compounds in excellent yields on treatment with 2molar amounts of acid anhydride and 10mol% of Yb(OTf)3 in MeCN at room temperature. Thus-formed diacyloxy compounds derived from aromatic aldehydes are reduced in situ by metallic zinc to afford the corresponding esters.
- Hirao, Toshikazu,Santhitikul, Sirida,Takeuchi, Hiroki,Ogawa, Akiya,Sakurai, Hidehiro
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p. 10147 - 10152
(2007/10/03)
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- The chemistry of acylals. Part I. The reactivity of acylals towards Grignard and organolithium reagents
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Aldehyde acylals have been prepared and reacted with Grignard and alkyllithium reagents. Acylals from formaldehyde furnished complex reaction mixtures when reacted with both reagents. Acylals of other aldehydes gave reaction mixtures that consisted mainly of an ester, generated by replacing one of the carboxy groups with the organic part of the organometallic reagent, and regenerated aldehyde. The esters were formed in the highest yields. Yields above 90% were experienced when the acylals were reacted with Grignard reagents under Barbier conditions.
- Sydnes, Leiv K.,Sandberg, Marcel
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p. 12679 - 12690
(2007/10/03)
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- Compositions for preserving crops and animal feedstuffs
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Fungus and mold growth in crops and organic matter are inhibited by the use of bis-carboxylic acid esters and compositions thereof. In a preferred embodiment, crops and animal feedstuffs are preserved during storage by applying a microbiocidal amount of a mono-, di or trioxymethylene, or lower alkylidene bis-alkanoate, or a mixture thereof.
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- Oxymethylene di-carboxylic acid esters as anti-fungal agents and animal growth promoters
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Fungal growth in animal feedstuffs is inhibited by the use of di-carboxylic acid esters and compositions thereof. In addition to inhibiting the growth of fungi, the di-carboxylic acid esters increase the nutritional value of the animal feedstuff treated, and promote greater weight gain and feed efficiency response in animals fed the treated feedstuff compositions.
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- Fungus and bacteria control with di-carboxylic acid esters
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Fungal and bacterial growth are inhibited by the use of di-carboxylic acid esters and compositions thereof. In a preferred embodiment, crops and animal feedstuffs are preserved during storage against fungal attack by applying a fungicidal amount of a mono-, di- or trioxymethylene, or lower alkylidene bis-alkanoate, or a mixture thereof. In another preferred embodiment, apple scab is controlled by applying to apple trees a fungicidal amount of a mono-, di- or trioxymethylene bis-alkanoate.
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