Berzelius by the dry distillation of tartaric or racemic acids (Pogg.
Since the molecule contains an asymmetric carbon atom, the acid exists in three forms, one being an inactive "racemic" mixture, and the other two being optically active forms. The inactive variety is known as paramandelic acid.
J.C.S., 1907, 1, p. 632), who showed that two racemic propyl tetrahydroberberines are produced when propyl dihydroberberine is reduced.
It may be prepared by heating racemic acid (see TARTARIC Acid) with fuming hydriodic acid; by heating fumaric acid (q.v.) with water at 150-200° C.; by the action of nitrous acid on inactive aspartic acid; and by the action of moist silver oxide on monobromsuccinic acid.
Four acids of this composition are known, namely dextroand laevo-tartaric acids, racemic acid and mesotartaric acid, the two last being optically inactive (see Stereo-Isomerism).
Their constitution follows from their formation from dibromosuccinic acid and from their synthesis from glyoxal cyanhydrin, these two methods producing the inactive racemic form which may then be split into the active components.
It may also be obtained (together with racemic acid) by oxidizing milk sugar, saccharic acid, &c., with nitric acid, and by the reduction of oxalic ester with sodium amalgam (H.
By mixing equal quantities of the two forms in aqueous solution heat is evolved and racemic acid, (C4H606)2.2H20, is obtained.
Pasteur, Ann., 1853, 88, p. 212); by heating tartaric or racemic acid for some time with water to 165° C.; by the oxidation of laevulose; and by the oxidation of phenol or maleic acid with an alkaline solution of potassium permanganate (0.
The alkaloids fall into two chemical groups: (i) derivatives of isoquinoline, including papaverine, narcotine, gnoscopine (racemic narcotine), narceine, laudanosine, laudanine, cotarnine, hydrocotarnine (the last two do not occur in opium), and (2) derivatives of phenanthrene, including morphine, codeine, thebaine.
The a-propyl piperidine so obtained is the inactive (racemic) form of conine, and it can be resolved into the dextroand laevo-varieties by means of dextro-tartaric acid, the d-conine d-tartrate with caustic soda giving d-conine closely resembling the naturally occurring alkaloid.
The trans compound is perfectly asymmetric and so its mirror image (I) should exist, and, as all the trans compounds synthetically prepared are optically inactive, they are presumably racemic compounds (see 0.
By mixing the d- and 1- forms, a racemic variety melting at 253° C. is.
The racemic trans-acid is produced by the reduction of the dihydrobromide of A 4 -tetrahydrophthalic acid or dihydrophthalic acid.
The trans-acid is a racemic compound, which on heating with acetyl chloride gives the anhydride of the cis-acid.