All the essential monosaccharides arise from glucose, by the conversions summarized in FIGURE 25.11. We'll not look specifically at these conversions, but might note that Problems 25-30 through 25-32 and 25-35 at the end of the chapter lead you through several of the biosynthetic pathways.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0921.jpg?height=442&width=1226&top_left_y=191&top_left_x=447)


Chain Shortening: The Wohl Degradation - 25.7 The Eight Essential Monosaccharides

FIGURE 25.11 An overview of biosynthetic pathways for the eight essential monosaccharides.
PROBLEM Show how neuraminic acid can arise by an aldol reaction of $N$-acetylmannosamine with pyruvate
25-24 $\left(\mathrm{CH}_{3} \mathrm{COCO}_{2}^{-}\right)$.
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$N$-Acetylmannosamine


Chain Shortening: The Wohl Degradation - 25.8 Disaccharides

We saw in Section 25.6 that reaction of a monosaccharide with an alcohol yields a glycoside in which the anomeric - OH group is replaced by an -OR substituent. If the alcohol is itself a sugar, the glycosidic product is a disaccharide.


Maltose and Cellobiose -

Disaccharides contain a glycosidic acetal bond between the anomeric carbon of one sugar and an - OH group at any position on the other sugar. A glycosidic bond between C 1 of the first sugar and the -OH at C 4 of the second sugar is particularly common. Such a bond is called a $1 \rightarrow 4$ link.


Maltose and Cellobiose -

The glycosidic bond to an anomeric carbon can be either $\alpha$ or $\beta$. Maltose, the disaccharide obtained by enzymecatalyzed hydrolysis of starch, consists of two $\alpha$-D-glucopyranose units joined by a $1 \rightarrow 4-\alpha$-glycoside bond. Cellobiose, the disaccharide obtained by partial hydrolysis of cellulose, consists of two $\beta$-D-glucopyranose units joined by a $1 \rightarrow 4-\beta$-glycoside bond.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0922.jpg?height=289&width=563&top_left_y=278&top_left_x=426)


Maltose and Cellobiose -

Maltose, a 1 $\rightarrow 4-\alpha$-glycoside
[4-O-( $\alpha$-D-glucopyranosyl)- $\alpha$-D-glucopyranose]
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0922.jpg?height=345&width=627&top_left_y=673&top_left_x=391)


Maltose and Cellobiose -

Cellobiose, a $1 \rightarrow 4-\beta$-glycoside [4-O-( $\beta$-D-glucopyranosyl)- $\beta$-D-glucopyranose]
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0922.jpg?height=954&width=657&top_left_y=212&top_left_x=1070)


Maltose and Cellobiose -

Maltose and cellobiose are both reducing sugars because the anomeric carbons on their right-hand glucopyranose units have hemiacetal groups and are in equilibrium with aldehyde forms. For a similar reason, both maltose and cellobiose exhibit mutarotation of $\alpha$ and $\beta$ anomers of the glucopyranose unit on the right.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0922.jpg?height=305&width=1359&top_left_y=1319&top_left_x=383)


Maltose and Cellobiose -

Despite the similarities of their structures, cellobiose and maltose have dramatically different biological properties. Cellobiose can't be digested by humans and can't be fermented by yeast. Maltose, however, is digested without difficulty and is fermented readily.


Maltose and Cellobiose -

PROBLEM Show the product you would obtain from the reaction of cellobiose with the following reagents:
25-25
(a) $\mathrm{NaBH}_{4}$
(b) $\mathrm{Br}_{2}, \mathrm{H}_{2} \mathrm{O}$
(c) $\mathrm{CH}_{3} \mathrm{COCl}$, pyridine


Lactose -

Lactose is a disaccharide that occurs naturally in both human and cow's milk. It is widely used in baking and in commercial milk formulas for infants. Like maltose and cellobiose, lactose is a reducing sugar. It exhibits mutarotation and is a $1 \rightarrow 4$ - $\beta$-linked glycoside. Unlike maltose and cellobiose, however, lactose contains two different monosaccharides-D-glucose and D-galactose-joined by a $\beta$-glycosidic bond between C 1 of galactose and C4 of glucose.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0923.jpg?height=489&width=1422&top_left_y=192&top_left_x=346)


Sucrose -

Sucrose, or ordinary table sugar, is probably the most abundant pure organic chemical in the world. Whether from sugar cane ( $20 \%$ sucrose by weight) or sugar beets ( $15 \%$ by weight), and whether raw or refined, all table sugar is sucrose.


Sucrose -

Sucrose is a disaccharide that yields 1 equivalent of glucose and 1 equivalent of fructose on hydrolysis. This 1:1 mixture of glucose and fructose is often referred to as invert sugar because the sign of optical rotation changes, or inverts, during the hydrolysis of sucrose $\left([\alpha]_{\mathrm{D}}=+66.5\right.$ ) to a glucose/ fructose mixture ( $[\alpha]_{\mathrm{D}}=-22.0$ ). Some insects, such as honeybees, have enzymes called invertases that catalyze the sucrose hydrolysis. Honey, in fact, is primarily a mixture of glucose, fructose, and sucrose.


Sucrose -

Unlike most other disaccharides, sucrose is not a reducing sugar and does not undergo mutarotation. These observations imply that sucrose is not a hemiacetal and that glucose and fructose must both be glycosides. This can happen only if the two sugars are joined by a glycoside link between the anomeric carbons of both sugars-C1 of glucose and C2 of fructose.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0923.jpg?height=361&width=700&top_left_y=1348&top_left_x=344)
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0923.jpg?height=332&width=687&top_left_y=1360&top_left_x=1077)


Sucrose -

Sucrose, a ( $1 \rightarrow 2$ ) glycoside
[ $\alpha$-D-Glucopyranosyl-( $1 \rightarrow 2$ ) $\boldsymbol{\beta}$ - D -fructofuranoside]


Sucrose - 25.9 Polysaccharides and Their Synthesis

Polysaccharides are complex carbohydrates in which tens, hundreds, or even thousands of simple sugars are linked together through glycoside bonds. Because they have only the one free anomeric -OH group at the end of a very long chain, polysaccharides aren't reducing sugars and don't show noticeable mutarotation. Cellulose and starch are the two most widely occurring polysaccharides.


Cellulose -

Cellulose consists of several thousand D-glucose units linked by $1 \rightarrow 4-\beta$-glycoside bonds like those in cellobiose. Different cellulose molecules then interact to form a large aggregate structure held together by hydrogen bonds.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0924.jpg?height=261&width=1183&top_left_y=189&top_left_x=471)


Cellulose -

Cellulose, a $\boldsymbol{\beta}$-(1 $\rightarrow 4$ )-D-Glucopyranoside polymer
Nature uses cellulose primarily as a structural material to impart strength and rigidity to plants. Leaves, grasses, and cotton, for instance, are primarily cellulose. Cellulose also serves as raw material for the manufacture of cellulose acetate, known commercially as acetate rayon, and cellulose nitrate, known as guncotton, which is the major ingredient in smokeless powder, the explosive propellant used in artillery shells and in ammunition for firearms.


Starch and Glycogen -

Potatoes, corn, and cereal grains contain large amounts of starch, a polymer of glucose in which the monosaccharide units are linked by $1 \rightarrow 4-\alpha$-glycoside bonds like those in maltose. Starch can be separated into two fractions: amylose and amylopectin. Amylose accounts for about $20 \%$ by weight of starch and consists of several hundred glucose molecules linked together by $1 \rightarrow 4-\alpha$-glycoside bonds.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0924.jpg?height=483&width=975&top_left_y=1016&top_left_x=575)


Amylose, an $\alpha$-(1 $\rightarrow 4)$-D-Glucopyranoside polymer -

Amylopectin accounts for the remaining $80 \%$ of starch and is more complex in structure than amylose. Unlike cellulose and amylose, which are linear polymers, amylopectin contains $1 \rightarrow 6-\alpha$-glycoside branches approximately every 25 glucose units.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0924.jpg?height=603&width=1042&top_left_y=1710&top_left_x=536)


Amylopectin: $a-(1 \rightarrow 4)$ links with $a$-( $1 \rightarrow 6$ ) branches
Starch is digested in the mouth and stomach by $\alpha$-glycosidases, which catalyze the hydrolysis of glycoside bonds and release individual molecules of glucose. Like most enzymes, $\alpha$-glycosidases are highly selective in their action. They hydrolyze only the $\alpha$-glycoside links in starch and leave the $\beta$-glycoside links in cellulose
untouched. Thus, humans can digest potatoes and grains but not grass and leaves.
Glycogen is a polysaccharide that serves the same energy storage function in animals that starch serves in plants. Dietary carbohydrates not needed for immediate energy are converted by the body into glycogen for long-term storage. Like the amylopectin found in starch, glycogen contains a complex branching structure with both $1 \rightarrow 4$ and $1 \rightarrow 6$ links (FIGURE 25.12). Glycogen molecules are larger than those of amylopectin-up to 100,000 glucose units-and contain even more branches.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0925.jpg?height=351&width=1096&top_left_y=491&top_left_x=512)


FIGURE 25.12 A representation of the structure of glycogen. The hexagons represent glucose units linked by $1 \rightarrow 4$ and $1 \rightarrow 6$ glycoside bonds.


Polysaccharide Synthesis -

With numerous - OH groups of similar reactivity, polysaccharides are so structurally complex that their laboratory synthesis has long been a particularly difficult problem. Several methods have recently been devised, however, that have greatly simplified the problem. Among these approaches is the glycal assembly method.


Polysaccharide Synthesis -

Easily prepared from the appropriate monosaccharide, a glycal is an unsaturated sugar with a $\mathrm{C} 1-\mathrm{C} 2$ double bond. To ready it for use in polysaccharide synthesis, the glycal is first protected at its primary - OH group by formation of a silyl ether (Section 17.8) and at its two adjacent secondary -OH groups by formation of a cyclic carbonate ester. Then, the protected glycal is epoxidized.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0925.jpg?height=291&width=1132&top_left_y=1383&top_left_x=491)

Treatment of the protected glycal epoxide in the presence of $\mathrm{ZnCl}_{2}$ as a Lewis acid with a second glycal having a free -OH group causes acid-catalyzed opening of the epoxide ring by $\mathrm{S}_{\mathrm{N}} 2$ backside attack (Section 18.6) and yields a disaccharide. The disaccharide is itself a glycal, so it can be epoxidized and coupled again to yield a trisaccharide, and so on. Using the appropriate sugars at each step, a great variety of polysaccharides can be prepared. After these sugars are linked, the silyl ethers and cyclic carbonate protecting groups are removed by hydrolysis.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0925.jpg?height=394&width=521&top_left_y=1966&top_left_x=496)
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0925.jpg?height=359&width=586&top_left_y=1956&top_left_x=1035)


Polysaccharide Synthesis -

A disaccharide glycal
Among the numerous complex polysaccharides that have been synthesized in the laboratory are several tumorassociated carbohydrate antigens (TACAs) that are currently being tested as potential vaccines for breast,
prostate, lung, colon, and ovarian cancers.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0926.jpg?height=391&width=1188&top_left_y=257&top_left_x=471)


Polysaccharide Synthesis - 25.10 Some Other Important Carbohydrates

In addition to the common carbohydrates mentioned in previous sections, there are a variety of important carbohydrate-derived materials. Their structural resemblance to sugars is clear, but they aren't simple aldoses or ketoses.


Deoxy sugars, as we saw in Section 25.7, have an oxygen atom "missing." That is, an -OH group is replaced by an $-H$. The most common deoxy sugar is 2-deoxyribose, a monosaccharide found in DNA (deoxyribonucleic acid). Note that 2-deoxyribose exists in water solution as a complex equilibrium mixture of both furanose and pyranose forms.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0926.jpg?height=397&width=1115&top_left_y=1078&top_left_x=527)


Amino sugars, such as D-glucosamine, have an -OH group replaced by an $-\mathrm{NH}_{2}$. The $N$-acetyl amide derived from D-glucosamine is the monosaccharide unit from which chitin, the hard crust that protects insects and shellfish, is made. Still other amino sugars are found in antibiotics such as streptomycin and gentamicin.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0926.jpg?height=481&width=1303&top_left_y=1624&top_left_x=411)


(8.0) CHEMISTRY MATTERS -


Sweetness -

Say the word sugar and most people immediately think of sweet-tasting candies, desserts, and such. In fact, most simple carbohydrates do taste sweet but the degree of sweetness varies greatly from one sugar to another. With sucrose (table sugar) as a reference point, fructose is nearly twice as sweet, but lactose is only about one-sixth as sweet. Comparisons are difficult, though, because perceived sweetness varies depending on the concentration of the solution being tasted and on personal opinion. Nevertheless, the ordering in TABLE 25.1 is generally accepted.


Sweetness -

The desire of many people to cut their caloric intake has led to the development of synthetic sweeteners such as saccharin, aspartame, acesulfame, and sucralose. All are far sweeter than natural sugars, so the choice of one or another depends on personal taste, government regulations, and (for baked goods) heat stability. Saccharin, the oldest synthetic sweetener, has been used for more than a century, although it has a somewhat metallic aftertaste. Doubts about its safety and potential carcinogenicity were raised in the early 1970s, but it has now been cleared of suspicion for human consumption.
![](https://cdn.mathpix.com/cropped/2025_02_06_5556f7656cbdcaa0f9a7g-0927.jpg?height=538&width=1134&top_left_y=1005&top_left_x=493)


Sweetness -

FIGURE 25.13 The real thing comes from sugarcane fields like this one. (credit: modification of work "Flowering sugarcane field" by "carrotmadman6"/Flickr, CC BY 2.0)


Sweetness -

TABLE 25.1 Sweetness of Some Sugars and Sugar Substitutes


Sweetness -

| Name | Type | Sweetness |
| :--- | :--- | :---: |
| Lactose | Disaccharide | 0.16 |
| Glucose | Monosaccharide | 0.75 |
| Sucrose | Disaccharide | 1.00 |
| Fructose | Monosaccharide | 1.75 |
| Cyclamate | Synthetic | 40 |
| Aspartame | Semisynthetic | 180 |
| Acesulfame-K | Synthetic | 200 |
| Saccharin | Synthetic | 350 |


Sweetness -


Sweetness -

| Name | Type | Sweetness |
| :--- | :--- | :---: |
| Sucralose | Semisynthetic | 600 |
| Alitame | Semisynthetic | 2,000 |
| Neotame | Semisynthetic | 6,000 |
| Advantame | Semisynthetic | 20,000 |