SUBJECTS camphoric acid

A microanalytical procedure was reported for determination of camphor (190). The method is based on the formation of camphor oxime. The oxime is subjected to acid hydrolysis and the resulting hydroxylamine reacted with formalin and... 

The first of the thermoplastic synthetic polymers to be developed was celluloid, made by combining nitrated cellulose (pure cotton subjected to nitric acid) and camphor (C10H16O), a plasticizer. The motivation was a search for a replacement for the ivory used in making billiard balls. It became a commercial product circa 1865, and is still used for making ping-pong balls. 

Nagai et al. carried out various transformations with camphor-fused amino[l,2,4]triazine 191 <1998JHC293> (Scheme 39). Reaction of 191 with chlorocarbonylsulfenyl chloride yielded the fused thiadiazolone 192 in high yield (83%). The same starting compound also proved to be suitable for the synthesis of the fused triazole derivative 193. To this end, 191 was first subjected to two subsequent transformations first by dimethylformamide dimethylacetal followed by treatment with hydroxylamine hydrochloride to give an Ar-hydroxyamidine 193 in 90% overall yield, and then this compound was treated with polyphosphoric acid to yield the fused triazole product 194 in 92% yield. 

Since Pasteur separated crystalline sodium ammonium tartrate manually in 1848, many researchers have worked on the subject of enantiomeric separation. In 1939 Henderson and Rule fully separated derivatives of camphor by column chromatography using lactose as a stationary phase material [1]. Gil-Av et al. [2] were able to separate amino acid derivatives on a polysiloxane-based stationary phase by gas chromatography (GC) in 1966. Since then many approaches for a successful distinction between enantiomers have been developed for capillary GC and liquid chromatography [3]. It is still a current topic for researchers searching for chiral separation with SciFinder [4] results in 812 hits and searching for chiral recognition leads to 285 hits for the year 2003 only. 

In order to determine the structure of the photochemical rearrangement product of carvone camphor in methanol, and to prove its structure, the research team of T. Gibson subjected the bicyclic carboxylic acid product to a degradation sequence, which commenced with the HVZ reaction, followed by dehydrohalogenation, dihydroxylation and glycol cleavage. 

Interaction between propiophenone and dimethylamine in the presence of formaldehyde yields the Mannich base which is subjected to Grignardization with benzyl magnesium chloride to yield a racemic mixture of the two diastereoisomers designated as a- and P-alcohol. Fractional crystallization helps in the separation ofa-J/form which is subsequentlyresolvedbyJ-camphor-sulphonic acid to obtain (+)-a-form. Thisisnowpropionylatedwithpropionicacidintheprsenceoftrimethylaminetiogivedextropropoxyphene which takes up a mole of hydrochloric acid to form the desired official compound. 

In the process of Trebouillet and De Besancele, the cellulose, which may be in the form of paper, cotton, or linen, is twice nitrated-first in the acid mixture employed in a previous operation and secondly, in a fresh mixture of 3 parts sulphuric acid of 1.83 specific gravity, and 2 parts concentrated nitric acid containing nitrous acid. After each nitration the mass is subjected to pressure, and is then carefully washed with water, to which, at the last, a small quantity of ammonia or caustic soda is added to remove the final traces of acid. The impregnation of the pyroxyline with the camphor is effected in a variety of ways. 

Six years later Myers (1903) used aqueous solutions of camphor to evaluate the olfactory sensitivity of a group of Murray Islanders. In addition, these individuals were asked to describe the odors of perfumes and other scents, and to indicate whether they liked or disliked them. The average olfactory acuity of the islanders was reported as being slightly higher than that of Scottish control subjects, and their likes and dislikes were noted as being quite similar (e.g., they disliked asafoetida, valeric acid, and civet, and liked musk, thyme and violet). 

Braconnet in 1833, is the oldest of the synthetic plastics. It is made by treating fibrous cellulose with a mbcture of nitric and sulfuric acids, and was first used in the form of a lacquer (See collodion). In 1870, John Wesley Hyatt and his brother patented the use of plasticized cellulose nitrate as a solid, moldable material, the first commercial thermoplastic (celluloid). Camphor was the first (and is still the best) plasticizer for CN, although many camphor substitutes have been developed. Alcohol is normally used as a volatile solvent to assist in plasticization, after which it is removed. Molded products of CN are extremely tough, but highly flammable and subject to discoloration in sunlight. CN is amendable to many decorative variations. Its principal uses today are in knife handles, table-teimis balls, and eyeglass frames. A mixture of nitric and sulfuric acids converts cellulose into cellulose nitrate pyroxylin is a less nitrated material and it has been useful for photographic film, collodion, and celluloid plastics. 

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