JPS5959682A - Aromatic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an 8-alkyl-1-oxas compound having the formula (wherein R represents an alkyl group having 1 to 4 carbon atoms) 'a' 4,5]] Decane-2-O. Formula (1) represents the possible stereoisomers and mixtures thereof.

The compounds of formula I make a unique and individual contribution to fragrance compositions. Each cis- of the compound of formula ■
and trans-isomer &? , upper body 1. Although it has been found that the aromatic properties of the isomers differ, the aromas of the isomers complement each other, and as a result it is preferable to use a mixture of isomers. The compounds represented by formula (1) have been found to be useful in a variety of aromatic compositions, including bases of woody, floral, fruity, oriental and resinous types.

Subi'rolactone of the present invention can be obtained by a number of methods.
! J: Jj! Many of the methods are the same as those described in the literature for lactone production. For example, U.S. Pat. No. 2,839,538 ill
: ; J, Jviolines and R, La1and
e, l-Oon+ptes, Rend, J (261)
, 1983 (1965,): , T. Moul
inos and R, La1anae, l-BullSoc
, Ohim, France j ID 75-8rl
(1971); G, ■, N1kishin and
V.D.

Vorob'ev, [engineering 5 vestiya A
kademii Nauk 5SSR.

OtdelenieKhimicheskikh Na
uk J No, i [] (1962) 1874-18
76; and C2Walling and E', S, Hu
ySer, i0rg, React ons
J (13).

114 (1963).

In the present invention, cis- and trans-spirolactone refers to a compound in which the alkyl group R and the oxygen bonded to the cyclohexyl ring are either cis or trans. , preferably in the presence of a catalytic amount of a free radical initiator such as tertiary butyl peroxide (approximately 0.05 to 0.5 equivalents) at a temperature sufficient to initiate the reaction (i.e., tertiary butyl peroxide). In the case of acrylic acid or esters of acrylic acid, such as lower alkyl esters, about 145-155"0 is preferred), and in the case of acrylic acid or esters of acrylic acid, such as lower alkyl esters, an excess of 5 to 15" is preferred.
Ds amount) to react with an appropriate amount of cyclohexanol? Including ¥4). This method corresponds to the isomer mixture of the starting alcohol (1-1, monomer mixture). The cis- and trans-isomers have a somewhat hot odor and can be separated by techniques known in the art such as column chromatography, preparative gas chromatography7, but the It is much more economical to use isomer mixtures.

As it happens, the aromas of the isomers are complementary, and for most fragrance compositions, the strength of the mixture is preferable to the individual components.

Table 1 provides fragrance car descriptions for a number of spirolactones having formula I prepared according to the method described above.
).

Table 1 R Incense Li0) T 3" Strong, creamy, lactone, coumarin, slightly cresyl tone C2H5" Intense, creamy, lactone,
Slightly Utsudiya-03)4. Utsdi, milk-like lactone, dry s-terminal 2 &'-C4H0“ Peach, apricot, lactone tertiary-04'H7 Utsdi, amber, weak infusion: New compounds, themselves as well as their production are form part of the invention.

Compounds in which R is isophyl or ethyl,
8-isopropyl-1-oxaspiro[4,5)decane-2-one and 8-ethyl-1-oxaspiro C
4,5]] Decane-2-O is particularly preferred for use in aromatic compositions; both have a strong aroma and good retention;
Ethyl compounds are much stronger. These compounds are
Although perceptibly guilty of each other, they are complementary and can often be used to one another's advantage. For example, a small amount of an ethyl compound can be added to an isoprotyl compound to intensify the creamy note if that is desired. Made from xanol and acrylic acid÷1−
It can be said that about 35% to 55 cis isomers and 45
% to 65, trans isomer of candy, usually 40%-50
A product consisting of the cis form of H and 50%-60 of the trans isomer is provided. The odor of this product is woody, milky, chrysanthemum-like, powdery, intense, and long-lasting. This compound 1, which has a milk-like lactone note, is made of sandalwood or vegetative oil, which is produced by a large number of expensive oils, and is a dried resin preparation acid with a coarse or moss-like oil. Used for things 1
``Lono is preferable to 11. In addition to these, 8-isopropyl-1-ogisasubiloCd', 5]decane-2-
Gin is an oriental blend or a flower.

4: Ryobu Ken'f Domo I'm looking down at I1.

Compounds in which 11 is ethyl, when prepared from p-ethylcyclohexanol, contain the same proportions of the isomer 1, usually 40% to 50% of the cis isomer and 50 to 6
Zero trans alien bodies are provided.

The ethyl compound Q is stronger than the isopropyl compound, creamy f, heron character τ i1, and this J) like; thick T rhyme and Kurilmilactone tone is desirable. Aroma II' acid compound! 1'J has gardenia, jasmine, and tuberose, C), 1, 1, 1, 4, 4, 4, 711, especially 711. It is: It has a strong apricot flavor and is particularly 6 ta d), 8
-Ethyl-1-ocinaspiroC4,51decane-2-one is usually used in small amounts to impart depth and richness to a broad aroma base.

ld J7x-C Cree-ε Is it a sad and depressing complex? In compositions where it is desirable to add 8-ethyl-1-
It has been found that it is preferable to use a mixture of oxaspiro(4,5]]decane-2-o and 8-isobrobyl-1-oxaspiroC4,5]]decane-2-o.The ethyl compound is an isopropyl compound. It blends well with the creamy note and also emphasizes it.To emphasize the creamy note of the iso70-bill derivative, add a small amount of ethyl derivative to the base, and the ethyl derivative is added to the in-70bill derivative. Such mixtures preferably contain from about 0.05% to 1.0% of the ethyl derivative, and from about 0.1% to [ 1,5
% is particularly clever. The presence of such high-quality ethyl derivatives enhances the creamy tone and can be used in expensive woody scents such as sandalwood where a rich, creamy, woody kelp aroma is highly desirable to obtain a natural sandalwood scent. It is most suitable for compositions with different colors.

Of course, if you want to emphasize the creaminess of the isopropyl fat conductor's woody notes, you can also use a higher ratio.

Compounds in which R is methyl or secondary butyl are also highly preferred for use in fragrance preparations. Compounds 1'-, i.e. 8-methyl-1-oxaspiroC4, in which R is methyl
, 5) For decane-2-one, its isomer ratio is approximately 40% cis and 60% trans. This compound has its own unique aroma. It has a remy lactone aromatic character that reminds me of the ethyl derivatives, but is slightly cresyl-like (reminiscent of coumarin), but not as fruity as the ethyl derivatives. The methyl compound is 8-ethyl-1-oxaspiro[
4,5]] It is also several times as strong as decan-2-o.

Soo-L is also useful in a wide variety of fragrance compositions where a creamy lactone tone is desired. Additionally, the coumarin note is particularly useful in coumarin-type specialty treatments and fragrance compositions where a coumarin-like note is desired.

A new compound in which R is sec-butyl, namely 8-sec-butyl-1-oxaspiro[: 4.5 ]]decane-2-o, is similarly prepared from p-sec-butylcyclohexanol and acrylic acid. about 60% to 45% cis and about 55% to 70% trans, usually 36
An isomer mixture of 46% cis isomer from 1 and 67% trans isomer from 57' is formed. The aroma of these mixtures is fruity with notes of peach and apricot. The secondary butyl compounds are particularly useful in imparting natural fruity notes to fragrance compositions. These notes are most desirable in floral bouquets such as white roses, jasmine, and daffodils and contribute to the natural character of the fragrance.

In addition to these, 8-secondary petite-1-oxaspiro(4,5)decane-2-one is useful in a wide variety of fragrance compositions, contributing not only to the aromatic properties but also being present in the composition. Mix it with other notes to emphasize it. For example, in expensive woody-type fragrance paces such as sandalwood and vetiver, secondary butyl compounds can be used to soften or modify expensive wood fragrances. In refined fragrances such as Shizoletaizo, secondary butyl compounds combine with notes of woody, moss, and citrus to add a modifying fruity aroma.

In particular, the use of compounds of formula I in fragrance compositions
A number of desirable effects which can be extracted are illustrated by examples of the addition of this compound to the bases of vetiver, sandalwood, moss, amber and poiterose.

The sandalwood, vetiver and moss compositions were well mixed and became thick and rich after adding the compound of formula (1). 41
The effects of b1 and 7 were further described for each compound's proboscis. In sandalwood and vetiver bases, 8-isopropyl-1-oxasubiro(4,5]tethenone-2-o has a η of 10% and 20%, respectively.
The expensive texture characteristic inherent in the base of these 7 sleeves is not emphasized, and the soft, reamy and beggars power 1 is increased. In the moss yarn 9 composition, isopropyl spirolactone of 15 is present1
- By doing so, it added the excellent mellow characteristic and became rounder.

Addition of 8-ethyl-1-oxasubiro[4,5]decan-2-one at 6% and 1.2% added sweet creaminess to the sandalwood and vetiver paces. The base fragrance, especially the vetiver fragrance, has become even stronger. This vetiver pace was added to 8-methyl-1-
Ogisaspiro [4,5]-]? It was also used to explain the coumarin properties of Kan-2-O. Removing 4% of the coumarin from the vetiver and adding 23% of the methylsugar lactone not only added a harsh, #salty lactone-like quality, but also returned some of the sweet, hay-like contribution of the coumarin.

The amber and white rose compositions illustrate the ability of the compound of formula I to nuance the base when used in very small amounts.

The amber composition was found to be creamier and more balanced after adding the compound of Formula 1. When used with 1% methylsugar lactone, the creamy note added strength and body, while the creamy, woody note of the isozorogyl compound became softer, creating a more sophisticated aroma. Since small amounts of ethyl subrolactone were found to be detrimental to this base and White Rose Pace, both paces were used to illustrate the aromatic properties of this compound. 0.0% ethyl compound.
When I added 0.05% strength to 11%, Amber Pace became more creamy with Hama J4, and when I added 0.03% to the White Rose base, it added desirable fat properties, making it more natural. Emphasized characteristics.

It has been found that white rose bases usually fuse better and become more natural by adding compounds of formula I. The 0.5% isopropyl compound has an effect somewhat similar to that of the ethyl compound, emphasizing the natural floral character of the parallax and utilizing an effect more strongly reminiscent of natural rose oil. 8-1!Second-class butyl-1-oxaspiro [4,51 decane-2-one is also 0.5%, natural mixed 1, note-y emphasis, VC blends with the fruity characteristics of the base, and The compound of formula I is present in the fragrance composition at about 0.01%, which provides a natural floral aroma that emphasizes and enhances the fragrance.
It can be used in the range from 1% to 60%. For very strong ethyl compounds, a practical range of 0.1% to 5% is preferred;
A range of from 1 to 30% is preferred.

The use and manipulation of fragrance bases is, of course, dependent on the desired effect and is limited only by the skill of the perfumer in the art. Even with the 5 and 30 degrees recommended above, creative perfumers may need even higher concentrations in some cases, especially if they are trying to create a special effect. It should not be construed as a limitation.

Fragrance compositions containing compounds of formula I can be used as fragrance bases for the production of perfumes and toilet waters by adding the usual alcoholic and aqueous diluents. For perfumes, a base of about 15 to 20 parts 1 is used, and for toiletries, about 2 to 5 parts of base is used.

Similarly, the pace compositions can be used to perfume soaps, cleaning products, cosmetics, etc.-8, 11. In these cases, base I of about 0.5 to about 21
f f '& can be used.

If the 'J-treatment of the present invention is preferred for carrying out the present invention, J:1 body side? (This is for illustrative purposes only.)

This 21. r, the example is merely illustrative, and the invention is limited only by the content of the scope of the claim. Fragrance ingredients are shown in the y11 section of Grano Per. If the M-1 additive is often referred to by a generic name, part name, or commercial name, use that name with the chemical name in parentheses. Analysis of the reaction product was carried out on 1/16 inch x 500 feet (1 inch =
2.54, 1 foot-3 [1,48 cnt,
), 2% Oarbowa,
'! 'l: f,=l: '/8'r 7 chi x 2
(17 (h, 2% ov-101 color 11 Izu 4 used Perkin E1mer 9 [1n gas' chromatograph /, r) t each yI'+'1 scent Then, the odor of the compound eluted from the outlet of the gas chromatograph was determined by law.
71.1 to 4-isofurobylcyclohexanol of 21177 at 143-150°C! (1, (1 mole)
of acrylic, 142.5' (1,0 mol) of 4-isoprobylcyclohegisanol and 14.69 (061
6 mol) of a mixture of tertiary butylbutylene
I gained strength in time. 143-150' further 111'1
．． Stupid, IT compound w mt pressure 7A distillation L Tatoko/')
, 142.11, 1 ugly y: 12s-141°C (1,
C1) (g)? Generate it. Shielded milky lactone, 2 dry odor. Minya I: According to gas chromatography, 5 liters. 99%: 44 cis form (odor: nonalactone, celery lactone), 56% trans form (omitted: strong Utsy, cinnamon, urine).

Produced in the same manner (also: 1-b 8-Nukiru 1-Okiyaspiro C' 4.5
]] Decane-2-one i￥#: 97-I 00℃ ([1,5ff#Hg
), Aroma: strong, creamy, lactone, coumarin, slightly cresyl. Analysis: Gas chromatography pure black 99+; 40% cis-free (fragrance: α”1)
60%) Lance form (Fragrance: Urine odor, milk-like lactone, slightly cresyl).

1-08-ethyl-1-oxaspiroC4,5:]]decan-2-one k: 1 2 1-1 30'C([], 5
gaH (7). Scent: Intense, reamy, lactone, and slightly wheezy.

Analysis: Junri 99% according to gas chromatography; 42
Chisis body (fragrance: creamy, fragrant) 58%l
・Rance (;1: (Fragrance: Slightly cinnamaldehyde, creamy lactone) 1-a8-4n Nisho Satyl-1-Mexasbiro [4,5
]] Decane-2-one jli waste: 164-180°Q (C1,5M,
)Tg). Yes = ()jl, tins, lactone, phase separation: 'II has a purity of 99% by gas chromatography
;37% cis isomer (odor: nonalactone, celery lactone) 66% trans isomer (weak leather-like odor, urine odor) 1-6 p, -,% tertiary butyl-1-Ogisusbiro C/1. ．． 5'] Decane-2-one boiling, l#, : 140-142°O (0,5yny
tbHg). Scent: Woody, amber. Analysis: According to gas chromatography, purity is 99%;
Lactone peach, nonalactone) 68% trans isomer (odor: urine, utdilactone) Example Use of a compound of formula I in a lactone 1j composition.

A Vetiver pace ingredient
Part Vetiver Oil Pulbon 290 Sanchlor 200 Hydroxycitronellal 9D Cinnamon Alcohol 50 Heli No. 1 Robin
60 coumarin
30 musk ketone (4-dibutyl-6,5-dinitro-2,6-dimethylacetophenone) 50 musk ambrette (6
-tertiary butenthyl-3-methyl-2,4-dinitroani7
-#3000 The vetiver base formulated as above was not mixed with Nagisa. Vetiver oil and other ingredients did not blend well, and the acids used for this purpose were problematic.

8-ethyl-1-oxaspiro[4',51decane-2
- Adding 9.96 parts (1.2 inches) of oysters added sweetness and creaminess, allowing the notes of koala to blend. Vetiver base supplemented with ethyl compound was more intense and natural, 200 parts (20%) of 8-inpropyl-1-oxaspiro['4.5]]decane-2- Even on the deep power, unusual notes are blended, and the expensive Utsuddi characteristic of Kaen Qiang. The base to which this compound was added had an overall softer texture, became creamier, and had a natural vetiver fragrance.

Pure 4770 M: 8-isopropyl-1-oxaspiro C4,5:]]decane-2-O and about 0-1% of 2) and 0.5% of 8-ethyl-1 instead of diluent. -oxaspiro[4,5]]decane-2-one? After one use of 200 parts of the mixture, the resulting aromatic base becomes creamier, more intense, and more natural.

In order to explain the effects of 8-methyl-1-oxaspiro[:4.5]]decane-2-O, 60 parts of the above base was removed from one shoe and an angle prescription was made. The base without the coumarin was thicker, more woody, and had none of the sweet hay of the coumarin.

8-Methyl-1-oxaspiro[4,5)decane-2-
When 260 parts (23%) of 3QJ was added to the base, a sweet fragrance similar to the aroma of coumarin, but with even more pronounced characteristics, was added, and a rounder vetiver flavor was added. It became fragrant.

B Sandalwood base component Part 5-(2,2,3-trimethylcyclobenter-6-en-1-yl)pentan-2-ol] Filter 0
0 musk ambrette (6-m triadic butyl-6-methyl-2,4-dinitroanisole) 50
Amyris oil 20
Hydro A° Cicitronellal
, 60 methylionone
100 yen, 1, benosyl fragrant
4009D[] As mentioned above, the sandalwood pace was somewhat thin, and the rope was also slow and lacked fullness.

By adding 5, [ ] parts (0,6 parts) of 8-ethyl-1-oxas (4,5) decan-2-one, the creaminess of the aroma is emphasized and the base is leprosy.

J. Sato-j Nachiko, Raru na Shirakusei Top Note Keio, Epko, 100 copies (10%) of 8-isofurovir-1-oxasubiro[4,5]]decane-2-o. Due to the power Ul\Roko, the Utsudi characteristic is emphasized, and IJS
The base was improved with the addition of innote and richness, resulting in a more desirable sandalwood aroma. approx. 1.1% force) 0.5
Using 100 parts of 8-ethyl-1-oxaspiro[4,5)decane-2-one containing 8-ethyl-1-oxas20[4,,5:]]decane-2-o The creamy note then becomes more pronounced, producing a more nacho-coral sandalwood aroma.

C moss base component
1.2 lemon oil terpene
70 Lime oil (distilled product) 50 Orange oil Calijoña
60 amyl salicylate, purified product
20 salicylic acid pencil
60 coumarin
50 heliotropin
80Folione■(
Givaudan) (methyl 2-octinoate) 104-
Acetyl-6-tert-butyl-1,1-dimethylin
40
Meichikumosu town bath sex MJ moon story
50Liliai"' (Givaudan)
(p-Tertiary Butyl-α-Methylhydrocinnamaldehyde) 100 Phenylethyl Alcohol 1 [)0 α-Terpineol 60 Hydroxycitronellal /
10 diethyl phthalate
120850 The moss base formulated as described above was such that the composition had no noticeable mixing (-) characteristic. 150 parts (15%) of 8-inpropyl-1-
The addition of oxaspiro C4,5) decane-2-one blends the dominant woody notes into the base, rounding out the overall woody notes and balancing the moss aroma.

D a Amber based soluble labdanato note
376.3 Padyuri γ111 Moyene (compounds of various strains), 19.8 Soluble penzoin p) fat
99. .

Vetiver Oki Pulbon
49.5 white 1 song oil east india
99. .

Mus de Sienne absolute (50% ethanol solution) 19.
8 Musk Amblet <6-m Tertiary Butyl-6-Methyl-2,4-Mitsunitroanisole) 4
9.5 musk ketone (4-m tert-butyl-3,5-dinitro-2,4-dimethylacetophenone)
49.5 vanillin
49.5 Non-irritating (furocoumarin-free) bergamot oil
69.3 Orange oil California C cold pressed)
49.50-Z base (mainly phenylethyl alcohol, citronellol, phenyl acetate) 49.5 Beaver Absolute (10% ethanol solution) 9.9 990.1 Citrus, animal and sweet notes as described above It was somewhat immiscible to the amber base formulated. 9.9 sound 1! , (1,0%) of 8-methyl-1-oxaspiro(4,5]]decane-2-o or 8-improgyl-1-oxaspiro[4,5]]decane-2-
By adding onke, the first and other disharmonious notes were blended into this oxalic acid. Methyl spirolactone makes the base stronger (adds lightness and body),
Make it creamier and sweeter? Increased. Isopropyl spirolactone has a creamy, mellow scent with a t of 4 and an amber aroma with a hint of vermilion.
occured.

0.49 parts ((1,05%) of 8-ethyl-1-oxaspiro[4,5)decane-2-one klre When added to the amber heath, it was creamy and had a creamy consistency similar to IW1.
Is there a characteristic that makes you feel sad? It had a power of 1, but the lactone effect was much stronger, and the labdanato note became even more pronounced.

E White Rose Base Ingredients Part Palmarodi Oil
400 ginger grass oil
100 geranium oil "Algerian" 50 citronellol
150 benzyl acetate
100 phenylethyl acetate
60 fugonyl ethyl alcohol
40 aldehyde mixtures (n-octatool, n-nonanal and n-
-decanal) 5-methylionone
20α-ionone 60 nonyl alcohol 1
095 The white rose base blended as described above contained fruity notes that do not mix. base? 0.2
5 parts (0.03%) of 8-ethyl-1-oxasubi0.
1” 4.5 ]] Decane-2-O or 5 parts (0,5
%) of 8-isopropyl-1-oxaspiro[4,5]
] When formulated with either decane-2-o or 8-w, sec-butyl-1-oxaspiro[4,5II decan-2-one, these discordant notes blend to form a homogeneous citric acid. It became a thing. Ethyl spirolactone and isopropyl spirolactone also accentuated the natural character of the rose fragrance by adding strength and imparting a desirable fatty, creamy character. By adding natural peach two-tone secondary butyl spirolactone,
The fruity character of the base was emphasized. All bases are
I found it to be a more desirable floral fragrance.

11. Person Sha Hao

Claims (1)

Claims: (1) an olfactory effective amount of a compound having the formula (wherein R represents an alkyl group having 1 to 4 carbon atoms) and at least one other An aromatic filamentous p-acid containing an olfactory agent. (2) The composition according to claim 1, wherein R is an alkyl group having 6 or 4 carbon atoms. (3) The compound is 8-methyl-1-oxaspiro[4,5
2. The composition of claim 1, wherein the composition is 1 decane-2-one. (4) 8-Methyl-1-oxas-20 (4,51 decan-2-one has 35%-45% cis isomer and 55%-
4. The composition of claim 3, which is a mixture of 65 trans isomers. (5) The compound is 8-ethyl-1-oxaspiro[4,5
2.) A composition according to claim 1, which is decane-2-one. (6) 8-Ethyl-1-oxas 20C4,5:]]decane-2-o with 40%-50% cis isomer and 50%
6. The composition of claim 5, wherein the composition is a mixture of -60% of the trans isomer. (7) The compound is 8-isozorobyl-1-oxaspiro (
Claim 2, which is 4,51 decane-2-one
(8) 8-Improgyl-1-oxaspiro[4,5'
1 decane-2-one is 65%-55%, preferably 4
0%-50% cis isomer and 45%-60%, preferably! 8. A composition according to claim 7, which is a mixture of 50'% - 60% trans isomers. (9) The compound is 8-sec-butyl-1-oxaspiro C
The composition according to claim 2, which is 4,5':l decane-2-one. (+o+ 8-Second-butyl-1-oxaspiro[4
, 51 decan-2-one has 30%-40%, preferably 66-46%, cis J< of 55%-70%
(11) The yarn L1 composition according to claim 9, which is a mixture of preferably 55% to 67% of the trans IIl form of Containing an olfactory effective amount of a mixture consisting of inpropyl-1-oxaspiroC'4.5 ]]decane-2-o and 8-ethyl-1-oxaspiro(4,5]]decane-2-o. , the composition according to claim 1. (12) The composition consists essentially of 8-isozorobyl-1
-40% of oxaspiroC4,5]]decane-2-O-
71 with 50% cis form and 50%-60 trans form
．． 99% to 99.95% of +1 compound and 40 of 8-ethyl-1-oxas20C4,5]]decane-2-o
%-51]% of the cis isomer and 50%-60% of the trans isomer.
'+: Claim scope fii'! Composition according to item 11. (wherein R represents an alkyl group having 1 to 4 carbon atoms) as a fragrance agent. 04) Use of 8-methyl-1-oxaspiroC4,5]]decane-2-o as a fragrance. (151' 8-ethyl-1-oxaspiro C4,5)
Use of decane-2-one as a fragrance. t16) 8-isopropyl-1-oxaspiro[4
, 5:) Use of decane-2-one as a fragrance. On 8-P, 2M-! Use of -y-ru1-o*fspiro(4,5]]f'kafu2-o as an aromatic agent. Compound 〇09) 8-methyl-1-oxaspiro[4,5)decane-2-one. (20) 8-ethyl-1-oxaspiro[: 4.
．． 5]]Decan-2-one (2J) 8-Second-butyl-1-oxasubiro[4
, 5:) Decane-2-one. (22) A compound of the formula (wherein R represents an alkyl group having 1 to 4 carbon atoms) as a fragrance agent. 7. A process for preparing a compound having the formula (wherein R is as defined above), comprising reacting with a compound having the formula (wherein R is methyl, ethyl or secondary butyl).