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.
Apple cider vinegar has a pH of 3.1, which means it's not the most acidic. If supplementing your diet with apple cider vinegar helps you eat fewer calories, it may help you lose weight. One pound of fat contains 3,500 calories, and if you're eating 250 fewer calories a day by taking apple cider vinegar, you'll lose 1/2 pound per week.