In this article we present a survey of the pigments found in the flowers and fruits of old and modern varieties of roses. The yellow colors are produced by carotenoids, the reds by anthocyanins, and the modern oranges by a mixture of the two. The great structural diversity of the carotenoids contrasts with a surprisingly small number of anthocyanins. For the carotenoids found in roses, a clear correspondence exists between the structure and the breeding partners used; the old yellow roses, which arose from crosses with Chinese varieties, mainly contain carotenoids from early stages in the biosynthesis, while in the modern yellow roses, which are descended from Central Asian foetidu types, hydroxylations, epoxidations, and epoxide transformations readily occur. A recently elucidated carotenoid degradation sequence follows the scheme C,, -+ C,, + C,, + C,, + CI4. The C,, compounds are odoriferous substances that contribute to the scent of roses. In the physiological pH region, copigmentation with flavonol glycosides is crucial for stabilization of the anthocyanin chromophores. Many roses, including the "apothecary's rose", which was once used medicinally, contain large amounts of strongly astringent ellagitannins, monosaccharide esters of gallic acid.654 0 VCH Verlagsgesellschafi mbH, W-6940 Weinheim. 1991 0570-0833i9lj0606-0654 8 3.50 + .25/0 Angew. Chem. In!. Ed. Engl. 30 (1991) 654-672 3 15 14' 1? 10' 8' 6 4' 2' 1, la, phytoene. Am,,=275/285/29a HO 12, a-kryptoxanlhtn (formerly zeinoxanthlnl. Am,,=L2Q/LLL/L72 OH 2, 2a, phytolluene. Am,,=331/3L7/367 HO 13, 13a. 13b, zeaxanlhin. Am,,=L50/L76 3,3a, 3b. <-carotene. A, , : 379/ LOO/ L2L HO 4,423, 4b. neurosporene. Am,,=Ll6/L38/L68 14, lutein lformerly xanthophylll. Am,,=L20/LLL/L72 HO * \ + O H p I \ \ H' #&, 5,5a -5e. lycopene. Am,,=LLL/L7Q/501 15, 3'-epilulein (formerly callhaxanlhinl, Am,,=L20/LLL/L72 6.6a, P,g-carotene [formerly I-carotene). Am,,=L35/L59/L89 HO 7,7a, 7b. p.P-carolene.Am,,=L5Q/L78 8,8a, E ,~I -carotene (formerly a-carotenel, Am,,-L20/LLL/L72 9, p,e-carotene lformerly 6-carotenel, A ,,,:L29/L55/L81 HO 10,lOa -I&, rubrxonthin 1/5'2J;gozanraxanthinJ. Am,,=L35/L60/L91 HO 17, 18RI-mulaloxanlhin, Am,,=L03/LZ6/L51 18, 18SI-mutatoxanthin. Am,,=LOL/L27/L52 19, 19a, violoxanthin. A,,,=~15/~38/~68 \ $ no 20,20a, 18Rl-luteoxanthtn. A ,,,398/L22/LL8 11, Ila -I l c , P-kryptoxanthin, Am,,=L5Q/L78Fig. I. Carotenoids isolated from roses and their bands in the visible in nm). Formula numbers with letters indicate all-2 compounds; those without letters are E isomers. The position of the E double bond is given by a wavy line from the preceding single bond; that is, a wavy line from C(14) to C(15) indicates the presence of a (152.1 5'2) double bond. Note that not only mono-2-carotenoids can occur, but that di-2 compounds, etc., are also found.

The Raman spectra (5800–40 cm−1) of the all‐trans and 15‐cis isomers of β‐carotene were observed in the solid state at 77 K and in cyclohexane solutions using laser lines of various wavelengths for excitation. The Raman spectra of the solid samples exhibited not only the well known strong bands but also a great number of sharp bands (mostly weak in intensity) which could not be observed or were observed broadly in solutions at room temperature. The molecules of both isomers in solution seem to have structures slightly different (‘relaxed’) from those in the solid state. All the bands in the region of 5800–1800 cm−1 were satisfactorily accounted for as overtones or combination tones of relatively strong fundamentals. Rough excitation profiles and depolarization degrees measured for cyclohexane solutions gave information on the mechanism of resonance enhancement. The polarized bands of the all‐trans isomer at 1597 and 1525 cm−1 are both resonant with the 1Bu←1Ag absorption around 480 nm. In addition, the 1597 cm−1 band is resonant with the 21Bu←1Ag absorption around 275 nm. The polarized bands at 1597, 1533, 1194, 1156 and 1004 cm−1 of the 15‐cis isomer are resonant with the ‘cis‐peak’ around 340 nm as well as with the 1B1←1A1 absorption around 475 nm. The polarized bands at 1241, 1052 and 953 cm−1 of the 15‐cis isomer are characteristic of this isomer, but these are only slightly resonant with the ‘cis‐peak’. The intensity of the depolarized band at 1564 cm−1 of the 15‐cis isomer is enhanced by the vibronic interaction between the excited 1A 1+ and 1B1 states.

Synthesis of Optically Pure Grasshopper Ketone and of Its Diastereoisomers and Related CompoundsStarting from our previously described synthon 1, the synthesis of four enantiomerically pure grasshopper ketons (diastereoisomeric 4-(2', 4'-dihydroxy-2', 6,6-trimethylcyclohexylidene)but-3-en-2-ons) and of their 0x0 derivatives was performed. Spectral and chiroptical data are presented.

Resonance Raman spectra of tetradesmethyl-P-carotene were recorded using nine laser lines in the visible region. In a KBr disk at 77 K, two strong fundamental bands (1523 and 1133 cm-') and their overtone and combination bands were observed to the fifth overtone region. Excitation profiles of nine Raman bands, including overtone and combination bands, were measured in isopentane solutions at 185 K. These were simulated by a simple two-dimensional model based on Albrecht's A-term, and a reliable set of parameters corresponding to the structure differences between the excited and ground electronic states was determined. The agreement between the observed and calculated excitation profiles was excellent, showing the adequacy of the model adopted.

Chemical Derivatization: Microscale Tests for the Presence of Common Functional Groups in Carotenoids -(16 refs.). -(EUGSTER, C. H.; Carotenoids 1A (1995) 71-80; Edited by Britton, G.; Liaaen-Jenson, S.; Pfander, H.; Birkhaeuser, Basel, Switz.; EN)