Cyanoborohydride. Utility and Applications in Organic Synthesis. A Review

Hutchins, Robert O.; Natale, Nicholas R.

doi:10.1080/00304947909354852

Cited by 143 publications

(45 citation statements)

References 163 publications

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“…NaBH 3 CN is known to reduce a wide variety of organic functional groups with remarkable selectivity, and it is highly soluble in several solvents, including water, alcohols, and THF. 19,20 Furthermore, NaBH 3 CN is stable in acid to pH 3, and Borch et al 21 found that the BH 3 CN Ϫ reduction of imines is pH-dependent. Because the reduction consumes acid, Borch et al used indicators while adding acid to maintain the pH.…”

Section: Synthesesmentioning

confidence: 99%

Modified polysulfones. VI. Preparation of polymer membrane materials containing benzimine and benzylamine groups as precursors for molecularly imprinted sensor devices

Robertson

Guiver

Bilodeau

et al. 2003

J. Polym. Sci. A Polym. Chem.

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A modified polysulfone containing benzylamine groups was synthesized as a reactive membrane material. Polysulfone was activated at the ortho-sulfone site by direct lithiation with n-butyllithium, and the resulting lithiated polysulfone was then reacted with benzonitrile; this yielded a polymer with pendant benzimine groups. The structure was confirmed by NMR and IR spectroscopy and by the transformation of imine to ketone by acid hydrolysis. The polymeric benzimine was also reduced to benzylamine with sodium cyanoborohydride in an acidic medium. The structure and degree of substitution of both benzylamine derivatives were determined by NMR and IR spectroscopy. The modified polysulfone containing benzylamine groups initiated the polymerization of N-carboxyanhydride of ␥-benzyl-L-glutamate [Glu(OBzl)-NCA]. The side-chain oligopeptide of Glu(OBzl)-NCA attached to polysulfone was converted into molecular recognition sites.

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Section: Synthesesmentioning

confidence: 99%

Modified polysulfones. VI. Preparation of polymer membrane materials containing benzimine and benzylamine groups as precursors for molecularly imprinted sensor devices

Robertson

Guiver

Bilodeau

et al. 2003

J. Polym. Sci. A Polym. Chem.

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“…For reaction with different amines, a given amount of reactant was added into a 20 g/L oxidized methylcellulose aqueous solution (Me-ox); then, an excess of reducing agent (NaBH 3 CN at a molar concentration five times the -C=O content) was added to reduce the intermediate imine as shown previously to obtain a stable linkage X-NH-CH 2 -R (R-CH=O was used for the oxidized polysaccharide chain) [12]. After addition of the reducing agent (here NaBH 3 CN), pH was stabilized at a value around 6 and left under stirring during 24 hours before isolation and purification.…”

Section: Methodsmentioning

confidence: 99%

“…The objective of this paper is to prepare oxidized methylcelluloses with different degrees of oxidation, to characterize the new polymers obtained and to perform different reactions with amines using the well known reaction of reductive amination [12]. Especially, we intend to point out the influence of oxidation of methylcellulose on reactivity and physical properties of these oxidized methylcelluloses in relation to possible developments.…”

Section: Figurementioning

confidence: 99%

Periodate Oxidation of Methylcellulose: Characterization and Properties of Oxidized Derivatives

Rinaudo

2010

Polymers

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Abstract:In this paper, the behavior of oxidized methylcelluloses is compared with that of the initial methylcellulose, an amphiphilic cellulose derivative. Methylcelluloses are important for many applications in the cosmetic and food industries. The mechanism of thermo-gelation of methylcellulose is briefly explained as well as the method of oxidation of polysaccharides. Then, our experiments involve the preparation of oxidized methylcelluloses: three degrees of oxidation are prepared and the new polymers are characterized by NMR, IR, SEC and rheology. Oxidation with periodate theoretically allows introduction of two aldehydic groups on C2-C3 glycol positions of anhydroglucose units. This reaction not only enhances the flexibility of the cellulosic backbone, but also causes a decrease in the molecular weight. In particular, the rheological behavior of methylcellulose and oxidized methylcellulose as a function of temperature is examined. The oxidized methylcelluloses prepared, being rich in aldehyde functions, become interesting intermediaries to prepare new cellulose derivatives. In this paper, three examples of reductive amination based on the reaction of modified methylcelluloses and −NH 2 groups of different molecules are described: -alanine produces a polyelectrolyte; chitosan and hyaluronan-ADH (derivative obtained with adipic dihydrazide allowing introduction of −NH 2 functions on HA backbone) are crosslinked and give new biocompatible hydrogels.

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“…The hydrogenation of pyridazinones with LiAlH 4 furnishes the partially reduced 1,4,5,6-tetrahydropyridazinones [10], which behave as nonsteroidal progesterone receptor ligands [11]. For saturation of the C=N bond in pyridazinones, sodium cyanoborohydride (NaBH 3 CN) was found to be a mild, simple and regioselective reducing agent; its application has been well documented and reviewed in detail [12]. In this way, the macrocyclic dilactam skeleton of peptidal antibiotics (e .…”

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confidence: 99%

Synthesis and structure of cycloalkane‐ and norbornane‐condensed 6‐aryl‐1,2,4,5‐tetrahydropyridazinones

Csende¹,

Hetényi²,

Stájer³

et al. 2004

Journal of Heterocyclic Chem

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Dedicated to Prof. Sándor Antus on the occasion of his 60 th birthday.The C=N double bond of certain cis-or trans-cycloalkane and diexo-or diendo-norbornane-condensed pyridazinones was reduced with NaBH 3 CN. The cis-or trans nature of the starting cycloalkane derivatives was always retained in the saturated products, with a high degree of diastereoselectivity: the hydrogen on the new stereocenter and the annelational hydrogen next to the carbonyl always exhibited the same steric orientation. The stereostructures were determined by means of nmr measurements and confirmed by molecular modelling. Numerous cycloalkane-condensed 4,5-dihydropyrid a z i n -3 ( 2H)-ones have recently been prepared [1-3] and dehydrogenated with SOCl 2 in benzene and with CuCl 2 in C H 3 CN [4,5] or reacted with Zn/HCl, which leads to a diastereoselective reductive ring contraction [6]. The selective reduction and ring transformation of pyridazinones and phthalazinones are carried out under similar conditions [7,8]. By cleavage of the N-N bond, the reduction of phthalazinones with BH 3 /THF affords α-s u b s t ituted 1,2-benzenedimethanamines [9]. The hydrogenation of pyridazinones with LiAlH 4 furnishes the partially reduced 1,4,5,6-tetrahydropyridazinones [10], which behave as nonsteroidal progesterone receptor ligands [11]. For saturation of the C=N bond in pyridazinones, sodium cyanoborohydride (NaBH 3 CN) was found to be a mild, simple and regioselective reducing agent; its application has been well documented and reviewed in detail [12]. In this way, the macrocyclic dilactam skeleton of peptidal antibiotics (e . g . glidobactin A) [13] and 1,2-diazetid-3-ones has been prepared [14].Our present investigation was focused on the saturation of cycloalkane-condensed pyridazinones by the application of NaBH 3 CN in an effort to attain diastereoselectivity. Results.For saturation of the double bond in the bicyclic c i s-or t r a n s-cyclohexane-and tricyclic, norbornane-condensed dihydropyridazinones 6 -1 0, 1 6 and 1 7, which are easily accessible v i a the reactions of c i s-or t r a n s-2 -p-t o l u o y l c ycloalkane-or d i e x o-and d i e n d o-n o r b o r n a n e c a r b o x y l i c acids [15] with hydrazine [1], NaBH 3 CN in MeOH solution was added in portions at 0 °C, followed by hydrochloric acid dropwise (Schemes 1 and 2). The mixtures were made slightly alkaline and extracted with C H 2 C l 2 and the products were purified by column chrom a t o g r a p h y. In all cases, only a single diastereomer could be isolated. The t r a n s dihydropyridazine 1 0 gave the saturated t r a n s product 1 5.For the diendo-norbornane-fused derivative 19, only a markedly poor (28%) yield was obtained, whereas all the other reactions resulted in the saturated derivatives in good to excellent yields (75-94%).

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Cyanoborohydride. Utility and Applications in Organic Synthesis. A Review

Cited by 143 publications

References 163 publications

Modified polysulfones. VI. Preparation of polymer membrane materials containing benzimine and benzylamine groups as precursors for molecularly imprinted sensor devices

Modified polysulfones. VI. Preparation of polymer membrane materials containing benzimine and benzylamine groups as precursors for molecularly imprinted sensor devices

Periodate Oxidation of Methylcellulose: Characterization and Properties of Oxidized Derivatives

Synthesis and structure of cycloalkane‐ and norbornane‐condensed 6‐aryl‐1,2,4,5‐tetrahydropyridazinones

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