| name | structure | comment | uses |
| Citronellal | *present in 2 forms *prep fom oxdn of citronellol or by redn of citral *by oxdn it form citral so they present in a mix ,separated by sod. Sulfite ,citral react e dil Na sulfite while citronellal e conc *it form crystalline product e bisulfite and addn on ethylenic or ald or both = & regeneration by NaCo3 rather than NaoH to prevent resinification or polymerization | perfumary and flavor 2-production of citral | |
| citral (oil of lemon grass) | *present in 4 isomers present in nature as mix * lemon like odor *in oil of cymbopogon citralus *citral separated from other oils by formn adduct e sod bisulfite , w citral a-sod bisulfite =insol citral b freely sol *it is example of ald that can be acetylated to give acetylated citral then give citral -enolacetate *citral after acidification give alc derivative eaisly acetylated by acetic anhydride *citral form condens product e cpds contain methylenr gps as acetone form psedo -ionone w cyclized in acid med to ionone (a ,B -ionone (B= violet odor ) citral a give the same reaction as it form adduct e alk cyanoacetic a while citral b is not | 1-powerful insect repellent 2-perfuming (violet odour) | |
| myrtenal (in spanish eucalyptus) | *obtained from oxdn of B -pinene *example of bicyclic ald) | ||
| Safranal ( from saffrol) | *example of ald prep from non volatile to volatile form *prep from glycoside Picrocrocin on treatment e acid or alkali give glucose + safranal | ||
| Benzaldhyde | *in kernels of bitter almond *can be prep by chemical methods eg by oxdn of toluene or benzyl alc | 1-chemical syn 2- flavor | |
| Cumaldehyde )cuminal ) in cumin | *isolated by bisulfite method *by oxdn give cumic acid | flavor in foor sauces | |
| Cinnamaldhyde (in oil of cassia & cinnamon) | *prep by sod bisulfite method (using dilute soln to give crystalline product) ,recover by NaCo3 , hot and conc sod bisulfite is avoided as add on ethylenic bond > double salt >water sol > can not be isolated | flavor | |
| P-anisaldhyde | *oxdn product of anethol *in anise oil *Bi-sulfite method | perfume | |
| Vanillin | *most import source if vanilla pods (3%) ,present in form of glycosides >by enz hyd give vanillin & purified by sod-bisulfite *on large scale by syn from 1-eugenol >alk >isoeug >Ac >acetyl isoeu >oxdn >vanillin acetate >oH ,H >vanillin 2-oxdn of lignin (polyner of isoeu) >hyd ?>isoeu 3-from guiacol (CHCl3/NaoH (riemer timann) >vanillin (P) and (O -vanillin)w if not official can be separated by chromatography *it give blue e FeCl3 *it is estimated either as phenols by heating e alk in cassia flask or as ald using bisulfite method | ||
| furfural (heterocyclic ald) | *1st fraction in many oils >washed e water >ext e ether >purified e sod bisulfite *give red col e aniline acetate *give ald reactions e fehlig ,Tollens ,bisulfite ,Br2 addn (C13=190 ,HNMR=9,s) | ||