Key Molecules with SMILES

1. Formaldehyde (HCHO) — most reactive carbonyl SMILES: C=O No alpha-carbon; no steric hindrance; undergoes Cannizzaro with conc. NaOH.

2. Acetaldehyde (CH3CHO) — simplest aldehyde with alpha-H SMILES: CC=O Alpha-C = CH3; undergoes aldol with dil. NaOH; positive Tollens' + iodoform.

3. Acetone (CH3COCH3) — simplest ketone SMILES: CC(C)=O 6 alpha-H (on both methyl groups); positive iodoform; negative Tollens'/Fehling's.

4. Benzaldehyde (C6H5CHO) — aromatic aldehyde, no alpha-H SMILES: O=Cc1ccccc1 No alpha-H → Cannizzaro with conc. NaOH; positive Tollens' and 2,4-DNP; negative iodoform.

5. Iodoform (CHI3) — product of haloform reaction SMILES: IC(I)I Yellow crystalline solid; characteristic antiseptic odor; MW = 393.7.

6. 3-Hydroxybutanal (aldol product) SMILES: CC(O)CC=O Beta-hydroxy aldehyde; product of acetaldehyde aldol condensation.

7. 2-Butenal / Crotonaldehyde (dehydration product) SMILES: C/C=$\frac{C}{C}$=O Alpha,beta-unsaturated aldehyde; formed by heating 3-hydroxybutanal.

8. Cinnamaldehyde (crossed aldol of acetaldehyde + benzaldehyde) SMILES: O=$\frac{C}{C}$=$\frac{C}{c1ccccc1}$ Aromatic alpha,beta-unsaturated aldehyde; naturally occurring compound.

9. Ethylbenzene (Clemmensen product of acetophenone) SMILES: CCc1ccccc1 Product: C6H5-CH2-CH3 from C6H5-CO-CH3 (Zn-Hg/HCl).

10. Cyanohydrin of acetaldehyde SMILES: CC(O)C#N From CH3CHO + HCN; contains both -OH and -CN; lactonitrile.