Oxanamide

Replacement of the carbamate function by an amide seems to be compatible with meprobamate-like activity in a compound formally derived from a 1,2-glycol. Oxidation of the commercially available aldehyde, 22, under controlled conditions affords the corresponding acid (23). This is then converted to its amide (24) via the acid chloride. Epoxidation by means of perphthalic acid affords oxanamide (25). ... 

This aldehyde is an intermediate in the synthesis of the tranquillizer oxanamide. Because both components of the aldol reaction are the same, no special precautions need to be taken to prevent side-reactions occurring. In the synthesis, the dehydration happened spontaneously. 

The (3-hydroxy carbonyl products of aldol reactions are often very easily dehydrated to give a, 3-unsaturated carbonyl compounds and, if you spot an a,p-unsaturated carbonyl group in the molecule, you should aim to make it by an aldol reaction. You will 6rst need to do an FGI to the P-hydroxy carbonyl compound, then disconnect as before, oxanamide intermediate retrosynthetic analysis... 

The synthesis of the minor tranquilliser Oxanamide (31) illustrates how C-X disconnexions and FGI can be added to this genera) plan. The molecule has amide and epoxide FGs. We know of one way to put in each of these groups — by C-N and C-O disconnection — so we must start here and decide the order of events later. This gives us an a,l3-unsaturated acid, so we can disconnect at the double bond. 

Oxanamide, a mild sedative, is synthesized from butanal in these five steps ... 

---