Camphor sulphonic acid

Prepared from commercially available (+)-camphor-10-sulphonic acid in a few steps... 

The dendrobatid toxin 25 ID (18) has been synthesized by a new approach which utilizes an iminium-vinylsilane cyclization to produce the (Z)-6-alkylidene-indolizidine ring-system in a stereospecific manner. The key intermediate (19) was prepared from L-proline and converted into toxin 25 ID (18) by reaction with paraformaldehyde and (+)-camphor-10-sulphonic acid in refluxing ethanol. The method is potentially a general one for forming unsaturated azacyclic rings, and it provides a convenient route to the pumiliotoxin A alkaloids.7... 

Fig. 9.33. Chromatograms illustrating the spectrum of applicability of chiral anion exchangers derived from cinchonan derivatives (reprinted with permission from Ref. 1388]) (mobile phase McOH-O.l M ammonium acetate (80 20) pHj = 6.0 T = 25°C flow rate. I ml/min UV detection) (unless otherwise stated), (a) r7.v-3-Aminocyclopentanc carboxylic acid as DNZ derivative on CSP 1. (b) Heptelidic acid on CSP Vll T = I0°C. (c) 2-(rm-Butylsulphonylmethyl) 3-phcnyl propionic acid on CSP IX. (d) Camphor-10-sulphonic acid on CSP II. (e) 3-(3-Carboxy-pipcrazin-I-yl)propyIphosphonic acid as DNP-dcrivative mobile phase MeOH-0.5 M ammonium acetate (90 10) pH., = 6.0. (f) Omcpra/ole on CSP IX mobile phase. ACN-O. I M ammonium acetate (65 35) pH., = 5.0 T = 0"C. (g) 3,4-Dihydro-2H-pyran-2-carboxylic acid (reprinted with permis.sion from Ref. [73]) (for structure of CSPs see Fig. 9.32).

Camphor-10-sulphonic acid C10H14O4S Calaire, China Camphor... 

Terpenoids are frequently used to introduce asymmetry into molecules (a classic example is isopinocamphenylborane), and the use of camphor to introduce chirality into lanthanide shift reagents is now established (see also the section on bicyclo[2,2,l]heptanes below). The difference in geminal nonequivalence of methylene hydrogens of diastereomeric ( —)-menthoxyacetamides has been used as a monitor for the optical resolution of amines, this being a development of earlier work using menthoxyacetates for diastereomeric alcohols. The optical purity of chiral amines can also be checked from the n.m.r. spectrum of the amides obtained with (-t-)-(lR,4R)-camphor-10-sulphonic acid. Use of a menthol ester to separate pseudoasymmetric ferrocenes has been described. ... 

In contrast, the conversion of cellulose with camphor-10-sulphonic acid via in situ activation with CDI is not efficient to obtain a chiral sulphonic acid ester of cellulose. Only very small amount of sulphonic acid ester functions can be introduced in agreement with results of the chemistry of low molecular weight alcohols regarding a much lower efficiency of CDI for the preparation of sulphonic acid esters [38],... 

Camphor-10-sulphonic acid was found to effect rearrangement of 2,2 -hydrazonaphthalene to 2,2 -diamino-1,1 -binaphthy1 with a low, temperature- and solvent-dependent enantioselectivity. The application of Dibal to the preparation of diamines from aminals,... 

In related work, the same researchers described a four-component domino reaction that allows the one-pot synthesis of highly complex spiro systems, i.e. spiro[indoline/acenaphthylene-3,4-pyrazolo[3,4-6]pyridine derivatives 59 and 60 from phertylhydrazine, 3-aminocrotononitrile, isatin or acenaphthylene-1,2-dione and cyclic 1,3-dicarbonyl compoimds, including cyclohexane-l,3-diones and barbituric or thiobaibituric acid, in the presence of ( )-camphor-10-sulphonic acid (CSA) as catalyst (Scheme 1.30). 

Camphor-10-sulphonic acids, particularly (-I-) camphor-10-sulphonic acid, have been used in many organic syntheses to induce optical activity in a finished product. 

Apart from certain carbohydrates, the most inexpensive source of chiral compounds is the terpenes. These are readily obtained from plant sources and encompass examples of many important functional groups These include alcohols such as (+)-menthol (22) and (-)-bomeol (23), ketones such as (+)-camphor (24), (+)-pulegone (25), (-)-menthone (26) and (-)-carvone (27), the aldehyde (+)-citronellal (28), (+)-camphor-10-sulphonic acid (29), and alkenes such as (+)-limonene (30) and (+)-a-pinene (31). (a)-Pinene provides a good illustration of the fact that naturally derived chiral compounds are not necessarily enantiomerically pure. Both enantiomers are readily available but the normal samples are only of around 90% e.e. Fortunately this is not a serious problem since procedures have been... 

Camphor-8-sulphonic acid, Tll.l Camphor-10-sulphonic acid, T12.2... 

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