If the chromic acid oxidation is performed with stoichiometric oxidant in the presence of diethyl ether as co-solvent (a method introduced by H.C. Brown), the epimerization of l-menthone to d-isomenthone is largely avoided.
Apple cider vinegar isn't likely to be effective for weight loss. Proponents of the apple cider vinegar diet claim that drinking a small amount of apple cider vinegar before meals or taking an apple cider vinegar supplement helps curb appetite and burn fat. However, there's little scientific support for these claims.
Some marketers proclaim that apple cider vinegar is high in fiber and therefore aids in weight loss. (Fiber provides bulk but is indigestible by the body, so foods high in fiber provide a feeling of fullness for fewer calories.) A daily dose is also said to control or minimize the appetite.