22. From cyclohexane. Reference 13. After treatment with 10. in Scheme I), which are important in heterocycli~,~-~ carbo~ yclic,~,~ and physiological'chemistry. Vilsmeier-Haack- Arnold formylation'by chloromethaniminium salb (9 or 10 in Scheme 11) to give malonaldehydes 4 is the most important of the known methods and may be applied to malonic acids, but mesityl and tert-alkyl malonic acids are merely decarboxylated under ...