Traditional Strong and Hindered Bases
We offer specialized bases, such as the phosphazene or Verkade's bases, as well as traditional bases, such as DBU, DBN, n-BuLi etc (Tables 2, 3 and 4). These traditional strong and/or hindered bases are well known and frequently used tools in organic synthesis. For example, Proton Sponge® reagent (Product No. 14795) is an extremely strong base for a tertiary amine. Protonation releases the strain of the two amines, resulting in a so-called "proton sponge". Table 1 lists the basicity strength for some of our traditional bases.
| Product Number | Product Name | MeCNpKBH+ |
|---|---|---|
| 90605 | 1,5,7-Triazabicyclo(4.4.0)dec-5-ene (TBD) | 25.98 |
| 69440 | 7-Methyl-1,5,7-triazabicyclo(4.4.0)dec-5-ene (MTBD) | 25.44 |
| 33481, 33482 | 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) | 24.33 |
| 33471 | 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) | 23.89 |
| 87844 | 1,1,3,3-Tetramethylguanidine (TMG) | 23.3 |
| 22709 | Quinuclidine | 19.51 |
| 87900 | 2,2,6,6-Tetramethylpiperidine (TMP) | 18.64 |
| 76850 | Pempidine (PMP) | 18.62 |
| 90780 | Tributlyamine | 18.09 |
| 90340 | Triethylamine | 18.46 |
| 33480 | 1,4-Diazabicyclo[2.2.2]octan (TED) | 18.29 |
| 27690 | Collidine | 14.77 |
| 62760 | 2,6-Lutidine (2,6-Dimethylpyridine) | 13.92 |
*Absolute values in acetonitrile. Data obtained from Prof. Dr. Schwesinger, University of Freiburg, Germany
The general strength of the traditional lithium bases follows the order:
LDA < MeLi < n-BuLi < sec-BuLi < tert-BuLi
| 27690 | Phosphazene base P2-t-Bu solution sym.-Collidine, 2,4,6-Trimethylpyridine, 2,4,6-Collidine puriss. p.a., ≥99.0% (GC) C8H11N Mr 121.8 108-75-8 100 mL, 500 mL |
| 20615 | 2-tert-Butyl-1,1,3,3-tetramethyl-guanidine purum, ≥97.0% (GC) C9H21N3 Mr 171.3 29166-72-1 5 mL, 25 mL |
| 33482 | 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) 2,3,4,6,7,8,9,10-Octahydropyrimidol[1,2-a]azepine H. Oediger, et al., Synthesis 1972, 591; N. Ono et al., Bull. Chem. Soc. Jpn. 1978, 51, 2401; C. G. Rao, Org. Prep. Proc. Intl. 1980, 12, 225; N. Ono et al., Bull. Chem. Soc. Jpn. 1979, 52 , 1716. puriss., ≥99.0% (GC) C9H16N2 Mr 152.2 [6674-22-2] 50 mL, 250 mL, 1 L |
| 33481 | 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) 2,3,4,6,7,8,9,10-Octahydropyrimidol[1,2-a]azepine purum, ≥98.0% (GC) C9H16N2 Mr 152.2 [6674-22-2] 50 mL, 250 mL, 1 L |
| 33471 | 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) Amidine base used for dehydrohalogenation reactions to olefins: H. Oediger, et al., Synthesis 1972, 591. purum, ≥98.0% (GC) C7H12N2 Mr 124.2 [3001-72-7] 25 mL, 100 mL, 500 mL |
| 33480 | 1,4-Diazabicyclo(2.2.2)octane (TED), Dabco, Triethylenediamine purum, ≥95% (NT) C6H12N2 Mr 112.18 280-57-9 100 g, 500 g |
| 36672 | N,N-Dicyclohexylmethylamine purum, ≥97.0% (GC) C13H25N Mr 195.35 7560-83-0 250 mL, 1L |
| 31960 | N,N-Diethylaniline, free of mono-compounds puriss. p.a., ≥99.5% (GC) C10H15N Mr 149.24 91-66-7 100 mL, 500 mL |
| 38395 | N,N-Diisopropyl-2-ethylbutylamine purum, ≥98.0% (GC) C12H27N Mr 185.35 200342-33-2 25 mL, 100 mL |
| 38431 | N,N-Diisopropylmethylamine purum, ≥98.0% (GC) C7H17N Mr 115.22 10342-97-9 10 mL, 50 mL |
| 38438 | N,N-Diisopropyl-3-pentylamine purum, ≥99.0% (GC) C11H25N Mr 171.33 68714-10-3 1 mL, 5 mL |
| 39430 | N,N-Dimethylaniline puriss. p.a., ≥99.5% (GC) C8H11N Mr 121.18 121-69-7 100 mL, 500 mL |
| 34775 | 2,6-Di-tert-butyl-4-methylpyridine A sterically hindered, non-nucleophilic base which distinguishes between Brvnsted (protonic) and Lewis acids. Enables the direct high-yield conversion of aldehydes and ketones to vinyl triflates. Synthesis 1980, 283; Org. Synth. 1990, 68, 138. Hindered base for the O-alkylation of carbohydrates with alkyl triflates: J. Arnarp, et al., Acta Chem. Scand. Ser. B 32, 4, 1978; J. M. Berry, L. D. Hall, Carbohydr. Res. 1976, 47, 307; M. G. Ambrose, A. W. Binkley, J. Org. Chem. 1983, 48, 674; Base for the conversion of carbonyls in vinyl triflates with triflic anhydrides; P. B. Stang, W. Treptow, Synthesis 1980, 283. M. E. Wright, S.R. Pulley, J. Org. Chem. 1989, 54, 2886; W. J. Scott, et al., Org. Synth. 1990, 68, 116. purum, ≥97.0% (GC) C14H23N Mr 205.3 [38222-83-2] 5 g, 25 g |
| 03440 | N-Ethyldiisopropylamine solution, H|nig's base, N,N-Diisopropylethylamine, Proton scavenger used in peptide coupling,1 enolboration,2 Pd(0)-catalyzed alkoxycarbonylation of allyl phosphates and acetates,3 and as a catalyst in vinyl sulfone synthesis.4 (1) J. Org. Chem. 1994, 59, 695. (2) ibid. 1993, 58, 7162. (3) ibid. 1993, 58, 1538, Synth. Commun. 1993, 23, 3073. Ref 4. purum, ≥98.0% (GC) C8H19N Mr 129.2 [7087-68-5] 50 mL, 250 mL, 1L |
| 62760 | 2,6-Lutidine, 2,6-Dimethylpyridine purum, ≥96% (GC) C7H9N Mr 107.16 108-48-5 100 mL, 500 mL |
| 69440 | 7-Methyl-1,5,7-triazabicyclo(4.4.0)dec-5-ene (MTBD) 1,3,4,6,7,8-Hexahydro-1-methyl-2H-pyrimido[1,2-a]pyrimidine purum, ≥98.0% (GC) C8H15N3 Mr 153.23 84030-20-6 5 mL, 25 mL |
| 76830 | 3,3,6,9,9-Pentamethyl-2,10-diazabicyclo-(4.4.0)dec-1-ene (PMDBD) 1,2,3,4,4a,5,6,7-Octahydro-2,2,4a,7,7-pentamethylnaphthyridine purum, ≥% (GC) C13H24N2 Mr 208.35 69340-58-5 1 g |
| 76850 | 1,2,2,6,6-Pentamethylpiperidine (PMP), pempidine One of the most strongly basic tertiary amines (sterically hindered and nonquaternizing): H. Z. Sommer et al., J. Org. Chem. 1971, 36, 824. purum, ≥99.0% (GC) C10H21N Mr 155.3 [79-55-0] 5 mL, 25 mL |
| 90340 | Triethylamine puriss. p.a., ≥99.5% (GC) C6H15N Mr 101.19 121-44-8 250 mL, 1 L, 2.5L |
| 87844 | 1,1,3,3-Tetramethylguanidine (TMG) puriss., ≥99.0% (GC) C5H13N3 Mr 115.18 80-70-6 50 mL, 250 mL |
| 14795 | N,N,N',N'-Tetramethyl-1,8-naphthalenediamine (Proton Sponge) Very strong base with weak nucleophilic character due to steric effects. J. Chem. Soc., Perkin Trans. 2 1991, 857; R.W. Alder et al., Chem. Commun. 1968, 723; R. L. Benoit et al., Can. J. Chem. 1987, 65, 996. purum, ≥99.0% (NT) C14H18N2 Mr 214.31 20734-58-1 10 g, 50 g |
| 87900 | 2,2,6,6-Tetramethylpiperidine (TMP) purum, ≥97.0% (GC) C9H19N Mr 141.26 768-66-1 10 mL, 50 mL |
| 90603 | 1,5,7-Triazabicylco(4.4.0)dec-5-ene on polystyrene bound to polystyrene crosslinked with 2% DVB, Polymer-supported, strong, hindered pentasubstituted guanidine base c(base): ~2.6 mmol/g resin 5 g, 25 g |
| 90605 | 1,5,7-Triazabicyclo(4.4.0)dec-5-ene, 1,3,4,6,7,8-Hexahydro-2H-pyrimido[1,2-a]pyrimidine (TBD) purum, ≥98.0% (T) C7H13N3 Mr 139.19 5807-14-7 10 g, 50 g |
| 90780 | Tributylamine puriss. p.a., ≥99.0% (GC) C12H27N Mr 185.36 102-82-9 100 mL, 500 mL |
| 90850 | 2,4,6-Tri-tert-butylpyridine purum, ≥98.0% (CHN) C17H29N Mr 247.43 20336-15-6 1 g, 5 g |
| 93438 | Tris(trimethylsilyl)amine purum, ≥97.0% (GC) C9H27NSi3 Mr 233.58 1586-73-8 5 g, 25 g |
| 22709 | Quinuclidine purum, ≥95% (NT) C7H13N Mr 111.19 100-76-5 5 g, 25 g |
| 20160 | Butyllithium solution, n-BuLi techn., ~1.6 M in hexane C4H9Li Mr 64.06 [109-72-8] 100 mL, 500 mL |
| 20164 | Butyllithium solution, n-BuLi techn., ~2.5 M in toluene C4H9Li Mr 64.06 [109-72-8] 100 mL, 500 mL |
| 20159 | Butyllithium solution, n-BuLi purum, ~2.7 M in heptane C4H9Li Mr 64.06 [109-72-8] 100 mL, 500 mL |
| 20161 | Butyllithium solution, n-BuLi purum, ~10 M in hexane C4H9Li Mr 64.06 [109-72-8] 100 mL |
| 20185 | sec-Butyllithium solution, sec-BuLi, Lithium-2-butanide purum, ~1.3 M in cyclohexane C4H9Li Mr 64.06 [598-30-1] 100 mL, 500 mL |
| 94439 | tert-Butyllithium solution, t-BuLi, lithium-2-methyl-2-propanide purum, 1.6-3.2 M in heptane C4H9Li Mr 64.06 [594-19-4] 100 mL |
| 20190 | tert-Butyllithium solution, t-BuLi, Lithium-2-methyl-2-propanide techn., ~1.5 M in pentane C4H9Li Mr 64.06 [594-19-4] 100 mL, 500 mL |
| 53200 | Hexyllithium solution purum, ~2.5 M in hexane [21369-64-2] 100 mL, 500 mL |
| 62491 | Lithium diisopropylamide solution, LDA ~2 M in THF/heptane/ethylbenzene, liquid, brown A non-pyrophoric LDA-THF complex. Strong, sterical hindered base used for the formation of carbaniones: Aldrichimica Acta,1984 17, 80. Lithium diisopropylamide as a hydride donor: Majewski M.; Tetrahedron Lett. 1988 29, 4057-60. The "3 + 2 intramolecular cycloaddition reaction of azomethine ylides generated from benzylic N-oxides: Roussi G., Heterocycles 1990, 31, 1445. techn. C6H14LiN Mr 107.1 [4111-54-0] 100 mL, 500 mL |
| 67740 | Methyllithium solution, MeLi purum, ~5% in diethyl ether (~1.6 M) CH3Li Mr 21.98 [917-54-4] 25 mL, 100 mL |
| 67737 | Methyllithium solution, MeLi purum, ~1 M in cumene/THF (~1.6 M) CH3Li Mr 21.98 [917-54-4] 50 mL, 250 mL $ |
| 67741 | Methyllithium lithium bromide complex solution Nucleophilic methylating agent used in the synthesis of other methyl organometallics and in the preparation of methyl lactones from carboxylic acids. J. Am. Chem. Soc. 1979, 101, 1455. Handbook of Reagents for Organic Synthesis: Acidic and Basic Reagents; Reich, H. J., Rigby, J. H., Eds.; John Wiley & Sons: New York, 1999 (Z33,820-6). techn., ~1.5 M in diethyl ether CH3LiBrLi Mr 108.8 [917-54-4] 100 mL, 500 mL |
| 60071 | Potassium bis(trimethylsilyl)amide solution, Hexamethyldisilazane potassium solution Sterically hindered base employed in selective cyclization: J. Org. Chem. 1993, 58, 6177, 6874. Also used in the preparation of lanthanide complexes: Organometallics 1993, 12, 2618, ibid. 1992, 11, 2003. ~0.5 M in toluene C8H18KNSi2 Mr 199.5 [40949-94-8] 100 mL, 500 mL |
| 60066 | Potassium bis(trimethylsilyl)amide, Hexamethyldisilazane potassium salt purum, ≥95.0% (T) C8H18KNSi2 Mr 199.5 [40949-94-8] 25 g, 100 g |
| 60100 | Potassium tert-butoxide techn., ≥94% (T) C4H9KO Mr 112.2 [865-47-4] 10 g, 100 g, 500 g |
| 60098 | Potassium tert-butoxide purum, ≥97.0% (T) C4H9KO Mr 112.2 [865-47-4] 100 g, 500 g |
| 60103 | Potassium tert-butoxide solution purum, ~1 M in tetrahydrofuran C4H9KO Mr 112.2 [865-47-4] 100 mL, 500 mL |
| 60102 | Potassium tert-butoxide solution techn., ~1 M in tert-butanol C4H9KO Mr 112.2 [865-47-4] 100 mL, 250 mL |
| 71337 | Sodium tert-butoxide purum, ≥97.0% (T) C4H9KO Mr 112.2 [865-48-5] 10 g, 100 g, 500 g |
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